Effect of Down-regulated Expression of cPouV and cNanog on Pluripotency of Chicken(Gallus gallus) Embryonic Stem Cells(cESCs)

To explore the pluripotency maintenance and update the functional influence of pluripotency genes cNanog and cPouV in chicken （ C,a/lus gallus） embry- onic stem cells （ cESCs）, the stable RNAi vectors pSuper-cNanog and pSuper-cPouV constructed previously were used to transfect cESCs. The mRNA levels of two target genes were detected with real- time PCR. These two genes were down-regulated since the 48^th and the down-reg-lation continued with the extension of time, the interference efficiency reached 65% at 96^th hour （P 〈0.05）. With the down-regulation of cNanog or cPouV gene, cESCs showed differentiation and prolifera- tion rate of these cells slowed down, the domed colony of these cells disappeared gradually when the edge of colony became irregular. At 96^th hour after transfection, the alkline phosphatase （AKP） and stage-specific embryonic antigen-1 （ SSEA-1 ） were not be detected in cNanog gene-knecked out eESCs, but it was done in that with cPouV gene -knocked out. The cPouV-suppressing cESCs were again transfected with pSuper-cNanog, the pluripotency markers AKP and SSEA-1 were both not found expressing at the 48^th hour. The results showed that cPouV and cNartog genes played an important role in maintaining pluripotency and self- renewal in cESCs, and cNanog gene was dominant. To sum up, our results may provide insights into the molecular regulation mechanism of avian during development.

Study on the role of JAK/STAT signaling pathway during chicken spermatogonial stem cells generation based on RNA-Seq

Spermatogonia! stem cells（SSCs） form the foundation for spermatogenesis and sustain male fertility.To explore the regulatory mechanisms of chicken SSCs generation,we obtained highly purified chicken embryonic stem cells（ESCs）,primordial germ cells（PGCs） and SSCs by fluorescence-activated cell sorting（FACS）.High-throughput analysis methods（RNA-Seq） were used to sequence the transcriptome level of these cells.Gene ontology and Kyoto encyclopedia of genes and genomes（KEGG） pathway enrichment were used to analyze RNA-Seq results.BMP4 was used to induce chicken ESCs differentiation to SSCs-like cells in vitro.The quantitative real-time（qRT）-PCR was used to detect the expression changes of the key genes.The results showed that 22 relevant critical pathways were found by RNA-Seq,one of them was the Janus kinase/signal transducer and activator of transcription（JAK/STAT） signaling pathway.Total of 103 related genes were detected in this pathway.Protein-protein interactions analysis found that 87 proteins were significantly related to 19 key proteins in this pathway.These 87 proteins were enriched in 21 biological processes and 18 signaling pathways.Moreover,during the differentiation of chicken ESCs to SSCs-like cells induced by BMP4 in vitro,JAK2 and STAT3 were activated.The qRT-PCR results showed that the expression trends of JAK2 and STAT3 were basically the same as in vivo.We concluded that JAK/STAT signaling pathway plays an important role in the process of chicken SSCs generation both in vivo and in vitro;it may achieve its function through multiple biological processes and other related pathways.

UBE2I stimulates female gonadal differentiation in chicken(Gallus gallus)embryos

Without known analogous sex-determining factors like SRY(sex determining region Y)in mammals,the chicken(Gallus gallus)sex determination mechanism still remains unclear,which highly restricts the biological research on chicken development and poultry single-sex reproduction.Here we not only characterized a new female-biased gene UBE2I and identified the expression pattern by qRT-PCR,but also described the functional role of UBE2I in the gonadal development of chicken embryos.Results showed that UBE2I exhibited a female-biased expression pattern in the early stage of PGCs(primordial germ cells)in embryonic gonads and robust expression in ovaries of newborn chickens.Most importantly,we successfully developed an effective method to interfere or overexpress UBE2I in chicken embryos through the intravascular injection.The qRT-PCR analysis showed that the sex-related genes(FOXL2,CYP19A1 and HINTW)in females were upregulated(P<0.05)under the overexpression of UBE2I and the sex-related genes(SOX9,DMRT1 and WT1)in females were downregulated(P<0.05)after interfering UBE2I.Furthermore,the change of UBE2I expression was associated with the level of estradiol and its receptors(AR and ESR),which suggests that UBE2I is necessary to initiate the female-specific development in chickens.In conclusion,this work demonstrates that UBE2I is a crucial sex differentiation-related gene in the embryonic development of chickens,which provides insights for further understanding the mechanism of sex determination in chickens.

Metabolic properties of chicken embryonic stem cells

Cellular energy metabolism correlates with cell fate,but the metabolic properties of chicken embryonic stem (chES) cells are poorly understood.Using a previously established chES cell model and electron microscopy (EM),we found that undifferentiated chES cells stored glycogen.Additionally,undifferentiated chES cells expressed lower levels of glucose transporter 1 (GLUT1) and phosphofructokinase (PFK) mRNAs but higher levels of hexokinase 1 (HK1) and glycogen synthase (GYS) mRNAs compared with control primary chicken embryonic fibroblast (CEF) cells,suggesting that chES cells direct glucose flux towards the glycogenic pathway.Moreover,we demonstrated that undifferentiated chES cells block gluconeogenic outflow and impede the accumulation of glucose-6-phosphate (G6P) from this pathway,as evidenced by the barely detectable levels of pyruvate carboxylase (PCX) and mitochondrial phosphoenolpyruvate carboxykinase (PCK2) mRNAs.Additionally,cell death occurred in undifferentiated chES cells as shown by Hoechst 33342 and propidium iodide (PI) double staining,but it could be rescued by exogenous G6P.However,we found that differentiated chES cells decreased the glycogen reserve through the use of PAS staining.Moreover,differentiated chES cells expressed higher levels of GLUT1,HK1 and PFK mRNAs,while the level of GYS mRNA remained similar in control CEF cells.These data indicate that undifferentiated chES cells continue to synthesize glycogen from glucose at the expense of G6P,while differentiated chES cells have a decreased glycogen reserve,which suggests that the amount of glycogen is indicative of the chES cell state.

shRNA-triggered RNAi inhibits expression of NDV NP gene in chicken embryo fibroblast

RNA interference(RNAi)technology is a powerful tool for identifying gene functions.Chicken embryo fibroblast(CEF)is an ideal model for studying the interaction between avian viruses and their hosts.To establish a methodological platform for RNAi studies in CEF,three plasmid vectors expressing short hairpin RNAs(shRNAs)targeted against the Newcastle disease virus(NDV)NP gene were constructed.One of them,ndv1,was proven effective on blocking viral replication in CEF and chicken embryos.Four hours prior to infection with NDV,the CEF was transfected with the plasmids by Silent-fect.An unrelated shRNA sequence(HK)was used in mock transfection.The expression of a potent shRNA resulted in up to 2.3,21.1 and 9.8 fold decreases in NP gene expression at 3,6 and 9 h post infection in CEF,respectively.The ndv1 was able to completely inhibit the replication of the virus in CEF within 48 post infection.Furthermore,the pathological changes in CEF caused by NDV were delayed,and the degree of pathological changes was lighter compared with the mock transfection in the presence of ndv1.When the complex of shRNASilent-fect and NDV was co-injected into the allantoic cavity of 10-day-old embryonated eggs with 10^(5) or 10^(6) ELD50 NDV,NDV replication was decreased by 94.14% and 62.15% after 17 h,respectively.These findings suggest that the newly synthesized NP protein is critical for NDV transcription and replication and provide a basis for identifying the functions of viral genes and screening for effective siRNAs against viruses in CEF and chicken embryo by RNAi.