鸡W染色体基因GPBP1在胚胎组织中的表达研究

Expression of chicken W chromosome gene GPBP1 in embryonic tissues

鸡W染色体为进化过程中保留下来的Z染色体高度退化后的拷贝,在机体发育和代谢等过程中发挥着重要作用。以鸡W染色体上富含GC启动子的结合蛋白(GPBP1)基因为对象,对其在胚胎发育过程中的表达和功能进行初步研究;根据GPBP1基因在W和Z染色体上序列的不同,设计特异性引物扩增其W拷贝(GPBP1-W)、Z拷贝(GPBP1-Z)及同时扩增W和Z拷贝(GPBP1-ZW),采用qPCR及Western blot技术分析其在胚胎发育过程中不同组织的表达量,并通过FAD诱导性反转探究其对性别表型的响应。结果表明:GPBP1-W在孵化6 d的胚胎性腺中高表达,且表达量随胚胎发育而升高。GPBP1-W和GPBP1-Z在所检测的孵化12 d的胚胎组织中均有表达,其中mRNA高表达于脾脏组织中,蛋白高表达于性腺组织中;GPBP1-Z mRNA和蛋白质在雄性组织中的表达量高于雌性。GPBP1-W表达受雌性向雄性性反转的影响而显著降低,但GPBP1-Z的表达不受性反转的影响。这一研究提示,鸡性染色体基因GPBP1在鸡胚的性腺和脾脏中表达量高,且其Z拷贝在性别间和各组织中存在剂量效应和转录后调控作用,而W拷贝可能在雌性的部分组织中作为Z拷贝的补偿以保证其生物学功能的发挥。

Chicken W chromosome is considered to be a highly degraded copy of the Z chromosome, which is retained during evolution and plays an important role in developmental and metabolic processes. In this study, the expression profile and potential function of GPBP1(GC-rich promoter binding protein 1), one of the W chromosome genes, was investigated. According to the difference of GPBP1 sequence between W and Z chromosome, we designed primers specific to W copy, Z copy and common to W and Z copy(GPBP1-W, GPBP1-Z and GPBP1-ZW), and expression levels of GPBP1 in different tissues during embryonic development were measured with qPCR and Western blot, followed by a fadrozole-induced sex reversal assay to explore its response to gonadal phenotype. The results showed that GPBP1-W was highly expressed in gonad at embryonic day 6 and the expression increased with the development of the embryo. There was no significant difference between the gonads and the tail for the expression of both GPBP1-Z and GPBP1-ZW. Both GPBP1-W and GPBP1-Z could be detected in all measured tissues at embryonic day 12, and were highly expressed in spleen at mRNA level, but highly expressed in gonad at protein level. The mRNA and protein expression of GPBP1-Z in most male tissues were higher than that of female tissues. In addition, GPBP1-W expression was significantly suppressed by fadrozole-induced female to male sexual reversal,while GPBP1-Z was not affected.In conclusion,chicken sex chromosome gene GPBP1 was highly expressed in the gonads and spleen of chick embryos,and its Z copy had different dosage effects and post transcriptional regulation in different tissues between different genders.Its W copy may serve as the compensation for Z copy in some female tissues to ensure its biological function.