MicroRNA-196a regulates bovine newborn ovary
MicroRNA-196a regulates bovine newborn ovary homeobox gene (NOBOX)expression during early embryogenesis
Swamy K Tripurani 1,Kyung-Bon Lee 2,Gabbine Wee 2,George W Smith 2,3and Jianbo Yao 1*
Background
The earliest stages of embryonic development in verte-brates primarily rely on the maternal RNA and proteins synthesized during oogenesis [1,2].The period of mater-nal control of embryonic development varies among spe-cies according to the onset of embryonic genome activation and the degradation of maternal gene products
[3].The major onset of embryonic genome activation begins during the two-cell stage in mice;the four-cell stage in humans,rats and pigs,and during the eight-cell to 16-cell stage in cattle and sheep [4].Upon fertilization,in mouse embryos,90percent of the maternal mRNA is degraded by the two-cell stage,coincident with the com-plete activation of the embryonic genome [5,6].There is direct evidence that maternal mRNA clearance is critical for early embryonic development.For example oocyte-specific c-mos mRNA,essential for regulating meiotic arrest at metaphase,is degraded soon after fertilization
*Correspondence:jianbo.yao@https://www.wendangku.net/doc/0d14198662.html, 1
Laboratory of Animal Biotechnology and Genomics,Division of Animal and Nutritional Sciences,West Virginia University,Morgantown,WV 26506,USA Full list of author information is available at the end of the article
?2011Tripurani et al;licensee BioMed Central Ltd.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://www.wendangku.net/doc/0d14198662.html,/licenses/by/2.0),which permits unrestricted use,distribution,and reproduction in any medium,provided the original work is properly cited.
and injection of c-mos protein into Xenopus two-cell embryos induces cleavage arrest[7].In mouse,maternal mRNA degradation is dependent on the3’untranslated region(3’UTR)of the mRNA transcript.For example, chimeric mRNAs composed of the c-mos coding region fused to the hypoxanthine phosphoribosyltransferase (Hprt)3’UTR have reduced rates of degradation follow-ing microinjection into mouse fertilized oocytes[8].Thus degradation of maternal mRNAs is critical to embryogen-esis and represents a conserved mechanism of vertebrate development.
Multiple negative regulatory mechanisms are critical for post-transcriptional regulation of maternal tran-scripts,such as transcript deadenylation and interaction with RNA-binding proteins in a nonspecific or sequence-specific fashion[9].Recent studies in zebrafish have established a role for microRNAs(miRNA)as key regulatory molecules targeting maternal mRNA for degradation during the maternal-to-embryonic transition (MET)[10].MicroRNAs are endogenous small noncod-ing RNAs that bind primarily to the3’UTR of target mRNAs to repress their translation and accelerate their decay[11].The majority of miRNAs are evolutionarily conserved across species boundaries and play essential roles in regulating many distinct processes such as ani-mal development and growth,cell differentiation,signal transduction,cancer,disease,virus immune defense, programmed cell death,insulin secretion and metabo-lism[12-14].
In recent years,several studies have revealed the sig-nificance of miRNAs in reproduction and embryonic development.For example,targeted disruption of Dicer, a key enzyme involved in miRNA processing and the synthesis of small interfering RNAs from long double-stranded RNA[15,16]in mice and zebrafish resulted in embryonic lethality due to abnormalities in morphogen-esis,cell division and chromosome organization[17-21]. In zebrafish,miR-430has been linked to maternal mRNA decay accompanying the maternal-to-embryonic transition[10].At the onset of embryonic genome acti-vation,the level of miR-430substantially increases and the miRNA targets several hundred maternally provided mRNAs by binding to the complementary sites in their 3’UTR and promotes their deadenylation[10].Further-more,miR-196a regulates mammalian development via targeting homoeobox clusters[22]and misexpression of miR-196a leads to specific eye anomalies in a dose-dependent manner in Xenopus laevis[23].
Newborn ovary homeobox gene(NOBOX)is a tran-scription factor,identified by in silico subtraction of expressed sequence tags(ESTs)derived from newborn ovaries in mice[24].NOBOX mRNA and protein are preferentially expressed in oocytes throughout folliculo-genesis[25].Nobox knockout mice are infertile due to disrupted folliculogenesis and expression of many germ-cell specific genes and miRNAs is perturbed in such ani-mals[25,26].Furthermore,mutations in the NOBOX gene associated with premature ovarian failure have been described in humans[27,28].We recently estab-lished a key role for NOBOX in bovine early embryonic development[29].Bovine NOBOX is stage-specifically expressed during oocyte maturation and early embryo-nic development and of maternal origin.Depletion of NOBOX in bovine zygotes by siRNA microinjection impaired embryo development to the blastocyst stage. Furthermore,knockdown of NOBOX affected the expression of genes from the embryonic genome critical to early development and expression of pluripotency genes was altered in the inner cell mass of NOBOX siRNA injected embryos that reached the blastocyst stage.However,despite its established role in folliculo-genesis and early embryonic development,the post-transcriptional regulation of NOBOX has not been investigated.Given the importance of NOBOX,as a maternal transcript critical for development,and observed depletion of NOBOX during MET,we hypothesized that NOBOX is targeted by miRNAs for silencing and/or degradation in early embryos.In this study we identified a miRNA(miR-196a)targeting bovine NOBOX,examined the temporal expression of miR-196a during bovine early embryonic development and determined the effect and specificity of miR-196a in regulating bovine NOBOX expression both exogenously (HeLa cells)and endogenously in early embryos. Results and Discussion
miR-196a binds to the3’UTR of bovine NOBOX MicroRNAs regulate mRNA translation rate by perfect or imperfect base pairing with the3’UTR regions of their targets[30].It has been predicted that one miRNA can potentially regulate translation of up to a hundred mRNAs,which creates a challenge for experi-mentally validating miRNA-specific targets[31].To identify miRNAs that potentially regulate NOBOX expression,we analyzed the3’UTR sequence of bovine NOBOX using the“Microinspector”algorithm to pre-dict potential miRNA target sites[32].miR-196a was chosen for further studies,because the predicted MRE in the bovine NOBOX3’UTR had a low predicted free energy of hybridization with the cognate miRNA(-19.8 kcal/mol),suggesting a stable miRNA:mRNA duplex within the9nucleotide(nt)seed region at the5’end of the miRNA(Figure1).This seed sequence is an impor-tant determinant of miRNA-induced repression of gene expression[33].RNA secondary structure prediction analysis using Mfold[34]revealed that the apparent miR-196a binding site was positioned on a hairpin-loop structure,in an exposed position,which might facilitate
miRNA accessibility.In addition,when the NOBOX sequence was analyzed with other miRNA target predic-tion algorithms,miR-196a always was listed as a top candidate miRNA,further indicating that miRNA-196a might be a potential post-transcriptional regulator of NOBOX in early embryos.The lack of conservation of miR-196a recognition sequence in bovine NOBOX might be due to the rapid drifting of3’UTR during evolution[31,35].Furthermore,it has been reported that a large fraction of bona fide targets of microRNA would be missed[10,31,36]if evolutionary conservation were used as the sole criterion for predicting targets. Moreover,recent studies support a functional role for this specific miRNA as miR-196a targets specific homeobox genes(HoxB8,HoxC8,HoxD8and HoxA7) in mouse embryos and mammalian cells and plays a major role in animal development[22].Thus,the func-tional role of miR-196a in regulation of NOBOX was further investigated.
miR-196a is spatio-temporally regulated during development
To determine the tissue specific expression pattern of miR-196a,quantitative real-time PCR was performed. As shown in Figure2A,miR-196a is expressed predomi-nantly in kidney;it is also detected significantly in fetal and adult ovary,brain and hypothalamus.A similar expression pattern was observed in mice where miR-196a is enriched in the kidney and adult reproductive tissues[37].In order to examine if miR-196a expression is inversely correlated to bovine NOBOX expression during early embryonic development,we analyzed miR-196expression during oocyte maturation and early embryogenesis.Expression analysis indicates that bovine miR-196a is increased in four-cell and eight-cell stage embryos relative to germinal vesicle stage oocytes and declines at morula and blastocyst stages(Figure2B). The increased expression level of miR-196a near the eight-cell stage of embryogenesis potentially indicates miR-196a involvement in maternal transcript degrada-tion during the maternal-to-zygotic transition,as was observed for miR-430in zebrafish[10]miR-427in Xenopus[38]and miR-290in mouse[20].Moreover, when the spatio-temporal expression pattern of miR-196a is compared with the expression pattern of bovine NOBOX during early embryogenesis,miR-196a expres-sion increases steadily from two-cell to eight-cell stage of embryogenesis,while NOBOX expression decreases gradually during the same period[29].Thus,the inverse relationship between miR-196a and NOBOX expression/ activity supports the proposed role of miR-196a as a physiological regulator of NOBOX during early embryogenesis.
miR-196a specifically suppresses the expression of bovine NOBOX
To confirm the binding of miR-196a to bovine NOBOX in vitro,HeLa cell transfection studies were conducted.
A significant inhibition of NOBOX expression was observed in HeLa cells ectopically expressing both NOBOX and miR-196a(Figure3A)relative to cells transfected with NOBOX alone.Semi-quantitative analy-sis of western blot data showed a significant inhibition of NOBOX expression in the miR-196a-transfected cells (Figure3B).These results unequivocally show that bovine NOBOX is regulated at the
post-transcriptional
level by miR-196a and further supports the hypothesis that miR-196a is responsible for the negative regulation of NOBOX.
Furthermore,luciferase reporter assays were per-formed to validate specificity of the miR-196a regulation of NOBOX through the predicted miR-196a recognition sequence in the3’UTR of NOBOX.NOBOX3’UTR sequence was inserted downstream of the firefly lucifer-ase coding region.Mutations in the predicted MRE in the3’UTR of the NOBOX for miR-196a were created such that interaction between miR-196a and NOBOX is compromised(Figure4A).Ectopic expression of miR-196a by transfection of miR-196a duplex into the HeLa cells suppressed activity of a chimeric luciferase con-struct containing the miR-196a MRE of NOBOX at its 3’end(Figure4B).Luciferase activity was restored when a four-base mismatch mutation was introduced into the seed region of the miRNA-196a recognition sequence in
A B
Tissue distribution of miR-196a analyzed by quantitative real-time PCR.
and abundance expressed as relative fold change using the sample
depicted).(B)Relative abundance of miR-196a in bovine oocytes and in
each).Quantity of miRNA was normalized relative to abundance of
change using the sample with the lowest value as the calibrator(n= A B
the NOBOX3’UTR(Figure4B).These data indicate the predicted MRE is critical for the direct and specific binding of miR-196a to NOBOX transcript.
miR-196a represses endogenous NOBOX in bovine early embryos
Since we determined in heterologous systems that miR-196a is capable of regulating NOBOX expression through direct binding to the3’UTR of its mRNA,the ability of miR-196a to regulate endogenous NOBOX expression in early embryos was determined.Microin-jection of miRNA mimics into zygotes has been utilized previously as a tool to determine effects of overexpres-sion of specific miRNAs in mouse and zebrafish embryos[39-41].Ectopic expression of miR-196a mimic in bovine embryos effectively reduced NOBOX protein expression in eight-cell embryos compared to uninjected and the negative control miRNA-injected embryos(Fig-ure5A).Furthermore,recent studies have suggested that miRNAs not only inhibit productive translation but also accelerates target mRNA decay[42,43].Microinjec-tion of miR-196a mimic in bovine embryos significantly reduced NOBOX mRNA levels in eight-cell embryos by more than80%relative to uninjected and negative con-trol miRNA-injected embryos(Figure5B).
The degradation of the untranslated maternal RNA pool is very critical to early embryonic development[1]. The translation potential of a maternal mRNA transcript is affected by the length of the poly(A)tail as it confers mRNA stability and stimulates translation via interaction of poly(A)binding protein(PABP)with the5’m7G cap [44,45].Moreover,maternal mRNAs are dependent on post-transcriptional and post-translational mechanisms to regulate their activity,as they cannot be repressed at the transcriptional level[9,46].Recent studies in zebra-fish and Xenopus found that miRNAs promote deadeny-lation of target mRNAs and induce maternal mRNA degradation/clearance during early embryogenesis [10,38],indicating that miRNA-induced clearance of maternal mRNAs might be a universal mechanism dur-ing MET.Thus,a similar mechanism is likely to be involved in the miR-196a negative regulation of NOBOX expression in bovine embryos during MET. miR-196a is an evolutionary conserved miRNA that has been identified in a wide range of vertebrate species. It is expressed from intergenic regions of HOX gene clusters,and targets several HOX genes in these clus-ters,which are known to play crucial roles during devel-opment[22,47,48].Recent studies showed that75%of tumors express high levels of miR-196a and miR-196a is involved in regulating key pathways such as AKT signal-ing,p53and WNT signaling pathways[49,50].It has also been reported that miR-196a is differently regulated during polycystic kidney disease suggesting that miR-196is important for normal functioning of kidney[51]. The involvement of miR-196a in regulating the expres-sion of NOBOX supports a new role of this miRNA in early embryonic development during MET. Conclusions
Collectively,our results demonstrate the ability of miR-196a to negatively regulate NOBOX expression in a sequence specific fashion and the ability of miR-196a to suppress NOBOX mRNA and protein in early embryos. Future studies of interest will investigate whether loss of miR-196a has any effect on the early embryonic devel-opment and identify putative miR-196a targets by next generation sequencing analysis of miR-196a depleted and wild type embryos.
Methods
Bioinformatics Analysis
To examine the possibility of NOBOX regulation by miRNAs,we searched for potential microRNA recogni-tion elements(MRE)in the NOBOX3’UTR using Microinspector http://bioinfo.uni-plovdiv.bg/microin-spector/,an algorithm for detection of
possible
interactions between miRNAs and target mRNA sequences[32].
Tissue collection,RNA isolation and microRNA expression analysis
Bovine tissue sample collection,total RNA isolation and miRNA expression analysis in multiple tissues,oocytes and early embryos were performed as described pre-viously[52].
Plasmid construction
The full-length bovine NOBOX mRNA sequence was amplified from bovine adult ovary cDNA samples by PCR using gene-specific primers containing restriction sites BamHI/XhoI(Additional file1,Table1for the list of primer sequences).The PCR product was digested with BamHI and XhoI enzymes and subsequently cloned into pcDNA3.1(Invitrogen,Carlsbad,CA)vec-tor digested with the same enzymes.pcDNA3.1:miR-NA196a was constructed by PCR amplifying a~220nt region of genomic sequence surrounding pre-miR-196a from bovine genomic DNA sample using primers con-taining restriction sites BamHI/XhoI(Additional file1, Table1for the list of primer sequences).The PCR product was digested and subsequently cloned into pcDNA3.1vector digested with BamHI and XhoI.For construction of a vector containing NOBOX-3’UTR fused to the3’end of a luciferase reporter,we used the dual luciferase pmirGLO vector(Promega,Madi-son,WI).The NOBOX3’UTR was amplified from pcDNA3.1:NOBOX construct using primers contain-ing restriction sites SacI/XbaI(Additional file1,Table 1for the list of primer sequences).The PCR product was digested with SacI and XbaI and subsequently cloned into dual luciferase pmirGLO vector digested with the same enzymes.Mutation of the mir-196a miRNA recognition element(MRE)in the NOBOX3’UTR was performed using the QuickChange site-direc-ted mutagenesis kit(Stratagene,Santaclara,CA) according to the manufacturer’s instructions.(Addi-tional file1,Table1for the list of primer sequences). Cell culture and Reporter assay
HeLa cells were cultured in DMEM(Invitrogen,Carls-bad,CA)containing10%FBS and1%penicillin/strepto-mycin(Invitrogen,Carlsbad,CA).For transient transfection,FuGENE6(Roche Applied Science,Indiana-polis,IN)was used according to manufacturer’s instruc-tions.Following transfection,cells were incubated for48 h before harvest for western blotting and luciferase
A
B
Microinjection of miR-196a mimic represses endogenous NOBOX expression in bovine early embryos.(A)Effect of microinjection on abundance of NOBOX protein in8-cell stage embryos as determined by immunocytochemical analysis using confocal spinning-disk microscopy(n=4pools of5-10embryos per treatment).Uninjected embryos and embryos injected with a nonspecific miRNA were used as controls.Nuclear DNA was stained with DAPI.(B)Effect of miR-196a mimic microinjection on abundance of NOBOX
embryos as determined by real-time PCR.Data were normalized relative to abundance of endogenous control ribosomal protein and are shown as mean±SEM(n=4pools of10embryos per treatment).Different letters indicate statistical difference(P<0.05).
assay.Luciferase assay was performed using the Dual-Glo luciferase assay system (Promega,Madison,WI)as described by the manufacturer.Firefly luciferase activity was normalized to renilla luciferase activity to adjust for variations in transfection efficiency among experiments.All transfection experiments were performed in quadru-plicate (n =4)with data averaged from four indepen-dent experiments.
Western blot analysis
Western blot was performed as previously described [53]with minor modifications.After 48h of transfec-tion,HeLa cell lysates were harvested and washed once with phosphate-buffered saline (PBS),suspended in 50μl of PBS,and mixed with an equal volume of Laemmli sample buffer (Bio-Rad,Hercules,CA).Protein samples (15μg/each)were separated on a 4-20%gradient polya-crylamide gel (Bio-Rad,Hercules,CA)and electroblotted onto a polyvinylindene difluoride (PVDF)membrane (Bio-Rad,Hercules,CA).Following transfer and block-ing in 5%nonfat dry milk in Tris-buffered saline con-taining 0.1%Tween-20(TBST)for one hour,the membrane was then incubated in NOBOX antibody (ab41612;Abcam,Cambridge,MA)diluted 1:100in blocking buffer overnight at 4°C.After washing three times with TBST,the membrane was incubated for 1h with horseradish peroxidase-conjugated goat anti-rabbit IgG (Pierce,Rockford,IL)diluted 1:10000in blocking solution.The membrane was washed again with TBST,followed by detection with SuperSignal West Pico Che-miluminescent Substrate (Pierce,Rockford,IL).The membrane was stripped in Restore Plus Western Blot Stripping Buffer (Pierce,Rockford,IL),followed by detection of b -actin (ACTB)protein (positive control)using anti-b -actin antibody (Ambion,Austin,TX)and horseradish peroxidase-conjugated goat anti-mouse IgG (Pierce,Rockford,IL).
Microinjection experiments
Procedures for in vitro maturation of oocytes (obtained from abattoir-derived ovaries)and in vitro fertilization to generate zygotes for microinjection and for subsequent embryo culture were conducted basically as described [54,55].Presumptive zygotes collected at 16-18hours post-fertilization (hpf)were used in all microinjection experiments.Mature miRNA-196a mimic (MIMAT0000226)and negative control cel-miR-67(CN-001000-01-05)were obtained from Dharmacon Technolo-gies (Dharmacon Inc,Lafayette,CO),and diluted with RNase free water to a final concentration of 10μM and 20μM before microinjection (The final concentration used for microinjection was 20μM based on initial experiments showing this concentration is more effective in repressing Nobox expression).Approximately 20pl of miRNA mimic
(20μM)was injected into the cytoplasm of zygotes using an inverted Nikon microscope equipped with micromani-pulators (Narishige International USA,Inc.,East Meadow,NY).Uninjected embryos and embryos injected with above negative control miRNA were used as control groups.Each group contained 25-30embryos per replicate (n =4).After microinjection,groups of embryos were cul-tured in 75-to 90-μl drops of potassium simplex optimiza-tion medium (KSOM)(Specialty Media,Phillipsburg,NJ)supplemented with 0.3%bovine serum albumin (BSA)until 72h after insemination at which time point embryos were collected.The efficiency of NOBOX mRNA/protein knockdown in miRNA-196a mimic injected and control embryos was determined by quantitative real-time PCR analysis and immunocytochemistry in eight-cell stage embryos as described previously [30].Imaging was per-formed using confocal spinning-disk microscopy.Optical sections every 1μm were acquired for each embryo and MetaMorph software (Universal Imaging,Downingtown,PA,USA)was used for image acquisition and analysis.
Statistical Analysis
One-way ANOVA using the general linear models (GLM)procedure of SAS were used to determine the significance of differences in mRNA abundance and between the treated samples and the controls where values resulted from the luciferase reporter assay,quan-titative real-time PCR and western blots.Different let-ters indicate significant differences (P <0.05).
Additional material
Acknowledgements
This work was supported by National Research Initiative Competitive Grant #2008-35203-19094from the USDA National Institute of Food and Agriculture (GWS),Agriculture and Food Research Initiative,Competitive Grant #2009-65203-05706from the USDA National Institute of Food and Agriculture (JY)and funds from the West Virginia Agricultural and Forestry Experiment
Station (Hatch project No.427).The study is published with the approval of the station director as scientific paper No.3098.
Author details
1
Laboratory of Animal Biotechnology and Genomics,Division of Animal and Nutritional Sciences,West Virginia University,Morgantown,WV 26506,USA.2
Laboratory of Mammalian Reproductive Biology and Genomics,Department of Animal Science,Michigan State University,East Lansing,MI 48824,USA.3
Department of Physiology,Michigan State University,East Lansing,MI 48824,USA.
Authors ’contributions
SKT designed and performed most of the experiments including expression analysis of miRNA,preparation of constructs,cell transfection and analysis of gene expression.SKT also drafted the manuscript.KBL and GW performed the microinjection experiments.GWS and JY designed the study and
supervised the experimental work.All authors read and approved the final manuscript.
Received:24January2011Accepted:6May2011Published:6May2011 References
1.Schultz RM:The molecular foundations of the maternal to zygotic
transition in the preimplantation embryo.Hum Reprod Update2002,
8(4):323-331.
2.Li L,Zheng P,Dean J:Maternal control of early mouse development.
Development2010,137(6):859-870.
3.DeRenzo C,Seydoux G:A clean start:degradation of maternal proteins at
the oocyte-to-embryo transition.Trends Cell Biol2004,14(8):420-426.
4.Telford NA,Watson AJ,Schultz GA:Transition from maternal to embryonic
control in early mammalian development:a comparison of several
species.Mol Reprod Dev1990,26(1):90-100.
5.Bachvarova R,De Leon V,Johnson A,Kaplan G,Paynton BV:Changes in
total RNA,polyadenylated RNA,and actin mRNA during meiotic
maturation of mouse oocytes.Dev Biol1985,108(2):325-331.
6.Paynton BV,Rempel R,Bachvarova R:Changes in state of adenylation and
time course of degradation of maternal mRNAs during oocyte
maturation and early embryonic development in the mouse.Dev Biol
1988,129(2):304-314.
7.Sagata N,Watanabe N,Vande Woude GF,Ikawa Y:The c-mos proto-
oncogene product is a cytostatic factor responsible for meiotic arrest in vertebrate eggs.Nature1989,342(6249):512-518.
8.Alizadeh Z,Kageyama SI,Aoki F:Degradation of maternal mRNA in
mouse embryos:selective degradation of specific mRNAs after
fertilization.Mol Reprod Dev2005,72(3):281-290.
9.Bettegowda A,Smith GW:Mechanisms of maternal mRNA regulation:
implications for mammalian early embryonic development.Front Biosci 2007,12:3713-3726.
10.Giraldez AJ,Mishima Y,Rihel J,Grocock RJ,Van Dongen S,Inoue K,
Enright AJ,Schier AF:Zebrafish MiR-430promotes deadenylation and
clearance of maternal mRNAs.Science2006,312(5770):75-79.
11.Bartel D:MicroRNAs::Genomics,Biogenesis,Mechanism,and Function.
Cell2004,116(2):281-297.
12.Ambros V:The functions of animal microRNAs.Nature2004,
431(7006):350-355.
13.He L,Hannon GJ:MicroRNAs:small RNAs with a big role in gene
regulation.Nat Rev Genet2004,5(7):522-531.
14.Wienholds E,Plasterk RHA:MicroRNA function in animal development.
FEBS Lett2005,579(26):5911-5922.
15.Carmell MA,Hannon GJ:RNase III enzymes and the initiation of gene
silencing.Nat Struct Mol Biol2004,11(3):214-218.
16.Jaskiewicz L,Filipowicz W:Role of Dicer in posttranscriptional RNA
silencing.Curr Top Microbiol Immunol2008,320:77-97.
17.Bernstein E,Kim SY,Carmell MA,Murchison EP,Alcorn H,Li MZ,Mills AA,
Elledge SJ,Anderson KV,Hannon GJ:Dicer is essential for mouse
development.Nat Genet2003,35(3):215-217.
18.Kanellopoulou C,Muljo SA,Kung AL,Ganesan S,Drapkin R,Jenuwein T,
Livingston DM,Rajewsky K:Dicer-deficient mouse embryonic stem cells are defective in differentiation and centromeric silencing.Gene Dev2005, 19(4):489-501.
19.Giraldez AJ,Cinalli RM,Glasner ME,Enright AJ,Thomson JM,Baskerville S,
Hammond SM,Bartel DP,Schier AF:MicroRNAs regulate brain
morphogenesis in zebrafish.Science2005,308(5723):833-838.
20.Tang F,Kaneda M,O’Carroll D,Hajkova P,Barton SC,Sun YA,Lee C,
Tarakhovsky A,Lao K,Surani MA:Maternal microRNAs are essential for
mouse zygotic development.Genes Dev2007,21(6):644-648.
21.Nagaraja AK,Andreu-Vieyra C,Franco HL,Ma L,Chen R,Han DY,Zhu H,
Agno JE,Gunaratne PH,DeMayo FJ,Matzuk MM:Deletion of Dicer in
somatic cells of the female reproductive tract causes sterility.Mol
Endocrinol2008,22(10):2336-2352.
22.Yekta S,Shih IH,Bartel DP:MicroRNA-directed cleavage of HOXB8mRNA.
Science2004,304(5670):594-596.
23.Qiu R,Liu Y,Wu JY,Liu K,Mo W,He R:Misexpression of miR-196a induces
eye anomaly in Xenopus laevis.Brain Res Bull2009,79(1):26-31.
24.Suzumori N,Yan C,Matzuk MM,Rajkovic A:Nobox is a homeobox-
encoding gene preferentially expressed in primordial and growing
oocytes.Mech Dev2002,111(1-2):137-141.
25.Rajkovic A,Pangas SA,Ballow D,Suzumori N,Matzuk MM:NOBOX
deficiency disrupts early folliculogenesis and oocyte-specific gene
expression.Science2004,305(5687):1157-1159.26.Choi Y,Qin Y,Berger MF,Ballow DJ,Bulyk ML,Rajkovic A:Microarray
analyses of newborn mouse ovaries lacking Nobox.Biol Reprod2007,
77(2):312-319.
27.Qin Y,Choi Y,Zhao H,Simpson JL,Chen ZJ,Rajkovic A:NOBOX homeobox
mutation causes premature ovarian failure.Am J Hum Genet2007,
81(3):576-581.
28.Qin Y,Shi Y,Zhao Y,Carson SA,Simpson JL,Chen ZJ:Mutation analysis of
NOBOX homeodomain in Chinese women with premature ovarian
failure.Fertil Steril2009,91(4Suppl):1507-1509.
29.Tripurani SK,Lee KB,Wang L,Wee G,Smith GW,Lee YS,Latham KE,Yao J:
A Novel Functional Role for the Oocyte-Specific Transcription Factor
Newborn Ovary Homeobox(NOBOX)during Early Embryonic
Development in Cattle.Endocrinology2011,152(3):1013-1023.
30.Rajewsky N:microRNA target predictions in animals.Nat Genet2006,
38(Suppl):S8-13.
31.Bartel DP:MicroRNAs:target recognition and regulatory functions.Cell
2009,136(2):215-233.
32.Rusinov V,Baev V,Minkov IN,Tabler M:MicroInspector:a web tool for
detection of miRNA binding sites in an RNA sequence.Nucleic Acids Res 2005,,33Web Server:W696-700.
33.Brennecke J,Stark A,Russell RB,Cohen SM:Principles of microRNA-target
recognition.PLoS Biol2005,3(3):e85.
34.Zuker M:Mfold web server for nucleic acid folding and hybridization
prediction.Nucleic Acids Research2003,31(13):3406.
35.Shen-Orr SS,Pilpel Y,Hunter CP:Composition and regulation of maternal
and zygotic transcriptomes reflects species-specific reproductive mode.
Genome Biol2010,11(6):R58.
36.Bentwich I:Prediction and validation of microRNAs and their targets.
FEBS Lett2005,579(26):5904-5910.
https://www.wendangku.net/doc/0d14198662.html,ndgraf P,Rusu M,Sheridan R,Sewer A,Iovino N,Aravin A,Pfeffer S,
Rice A,Kamphorst AO,Landthaler M,Lin C,Socci ND,Hermida L,Fulci V, Chiaretti S,FoàR,Schliwka J,Fuchs U,Novosel A,Müller RU,Schermer B, Bissels U,Inman J,Phan Q,Chien M,Weir DB,Choksi R,De Vita G,
Frezzetti D,Trompeter HI,et al:A mammalian microRNA expression
atlas based on small RNA library sequencing.Cell2007,
129(7):1401-1414.
38.Lund E,Liu M,Hartley RS,Sheets MD,Dahlberg JE:Deadenylation of
maternal mRNAs mediated by miR-427in Xenopus laevis embryos.RNA 2009,15(12):2351-2363.
39.Krützfeldt J,Poy MN,Stoffel M:Strategies to determine the biological
function of microRNAs.Nat Genet2006,38(Suppl):S14-19.
40.Begemann G:MicroRNAs and RNA interference in zebrafish
development.Zebrafish2008,5(2):111-119.
41.Spruce T,Pernaute B,Di-Gregorio A,Cobb BS,Merkenschlager M,
Manzanares M,Rodriguez TA:An early developmental role for miRNAs in the maintenance of extraembryonic stem cells in the mouse embryo.
Dev Cell2010,19(2):207-219.
42.Bagga S,Bracht J,Hunter S,Massirer K,Holtz J,Eachus R,Pasquinelli AE:
Regulation by let-7and lin-4miRNAs results in target mRNA
degradation.Cell2005,122(4):553-563.
43.Lim LP,Lau NC,Garrett-Engele P,Grimson A,Schelter JM,Castle J,
Bartel DP,Linsley PS,Johnson JM:Microarray analysis shows that some
microRNAs downregulate large numbers of target mRNAs.Nature2005, 433(7027):769-773.
44.Curtis D,Lehmann R,Zamore PD:Translational regulation in
development.Cell1995,81(2):171-178.
45.Amano:Mechanism of Translation in the period of oocyte to zygote
trasition in mammals.JMammOva Res2005,1-11.
46.Vasudevan S,Seli E,Steitz JA:Metazoan oocyte and early embryo
development program:a progression through translation regulatory
cascades.Gene Dev2006,20(2):138-146.
47.Sehm T,Sachse C,Frenzel C,Echeverri K:miR-196is an essential early-
stage regulator of tail regeneration,upstream of key spinal cord
patterning events.Dev Biol2009,334(2):468-480.
48.Braig S,Mueller DW,Rothhammer T,Bosserhoff AK:MicroRNA miR-196a is
a central regulator of HOX-B7and BMP4expression in malignant
melanoma.Cell Mol Life Sci2010,67(20):3535-3548.
49.Andl T,Murchison EP,Liu F,Zhang Y,Yunta-Gonzalez M,Tobias JW,
Andl CD,Seykora JT,Hannon GJ,Millar SE:The miRNA-processing enzyme dicer is essential for the morphogenesis and maintenance of hair
follicles.Curr Biol2006,16(10):1041-1049.
50.Schimanski CC,Frerichs K,Rahman F,Berger M,Lang H,Galle PR,
Moehler M,Gockel I:High miR-196a levels promote the oncogenic
phenotype of colorectal cancer cells.World J Gastroenterol2009,
15(17):2089-2096.
51.Pandey P,Brors B,Srivastava PK,Bott A,Boehn SNE,Groene HJ,Gretz N:
Microarray-based approach identifies microRNAs and their target
functional patterns in polycystic kidney disease.BMC Genomics2008,
9:624.
52.Tripurani SK,Xiao C,Salem M,Yao J:Cloning and analysis of fetal ovary
microRNAs in cattle.Anim Reprod Sci2010,120(1-4):16-22.
53.Tejomurtula J,Lee KB,Tripurani SK,Smith GW,Yao J:Role of importin
alpha8,a new member of the importin alpha family of nuclear transport proteins,in early embryonic development in cattle.Biol Reprod2009,
81(2):333-342.
54.Bettegowda A,Patel OV,Ireland JJ,Smith GW:Quantitative analysis of
messenger RNA abundance for ribosomal protein L-15,cyclophilin-A,
phosphoglycerokinase,beta-glucuronidase,glyceraldehyde3-phosphate dehydrogenase,beta-actin,and histone H2A during bovine oocyte
maturation and early embryogenesis in vitro.Mol Reprod Dev2006,
73(3):267-278.
55.Bettegowda A,Yao J,Sen A,Li Q,Lee KB,Kobayashi Y,Patel OV,
Coussens PM,Ireland JJ,Smith GW:JY-1,an oocyte-specific gene,
regulates granulosa cell function and early embryonic development in cattle.Proc Natl Acad Sci USA2007,104(45):17602-17607.