摘要
用RACE-PCR方法从原肠期SMART文库中扩增到银鲫pou2基因的全长cDNA,其全长为2421bp,开放阅读框为1416bp,编码471个氨基酸,与斑马鱼pou2基因的氨基酸序列一致性高达91.0%。我们用RT-PCR和整体原位杂交的方法研究了银鲫pou2基因在胚胎发育过程中的时空表达图式。RT-PCR结果显示,银鲫pou2基因有母源转录本,其合子基因在高囊胚期强烈表达,在50%下包期和90%下包期也有高量的转录本,但在100%下包期表达量急剧降低,至体节期时已经完全检测不到其转录本。胚胎整体原位杂交结果显示其母源转录本在所有的胚盘细胞中。在高囊胚期和50%下包期,高度表达的合子转录本仍在所有的胚盘细胞中,但至90%下包期时,pou2的表达向胚胎背部的正中线汇聚,集中在神经板的两侧区域和脑部的两条横向条带。在100%下包期时,pou2的表达集中在神经板的中间区域以及预期形成的中后脑区域。至体节期时,转录本消失,这与RT-PCR结果高度一致。银鲫pou2基因的表达图式提示该基因在胚胎发育的早期具有重要作用,它可能参与调控神经板的形成和中后脑细胞的发育命运。
Full-length cDNA of Gibel carp pou2 gene was cloned from gastrula SMART cDNA library through RACE-PCR. It consists of 2421bp, with an ORF of 1416 bp encoding a protein of 471aa. The complete amino acid sequence shares 91.0% identity with zebrafish pou2 gene product. Temporal and spatial expression pattern of gibel carp pou2 during embryogenesis was investigated by RT-PCR and whole-mount in situ hybridization. RT-PCR result indicates that there is maternal transcript of gibel carp pou2 in early embryos and the zygotic pou2 transcript is abundantly expressed from blastula stage. Large amount of pou2 transcript is detected at both 50% and 90% epiboly stages. At 100% epiboly stage, however, the pou2 transcript reduces rapidly and disappears at the later embryogenesis. Whole-mount in situ hybridization shows that the maternal transcript ubiquitously exists in all blastomere cells. In blastula embryos and 50% epiboly embryos, the zygotic pou2 transcript is also distributed in every blastomere cell. At the stage of 90% epiboly, expression of pou2 converges to the dorsal midline of embryos and locates in two waves of lateral neural plate and two transverse stripes in the brain region. In embryos at 100% epiboly, pou2 transcript is restricted in the neural plate and areas of presumptive midbrain and hindbrain. From somite stage, gibel carp pou2 can not be detected any more, which is consistent with the RT-PCR result. The expression pattern of gibel carp pou2 suggests that this gene should play an important role during early stages of embryogenesis. It might regulate the formation of neural plate and the fate of midbrain and hindbrain cells during early embryogenesis.
出处
《水生生物学报》
CAS
CSCD
北大核心
2007年第5期629-636,共8页
Acta Hydrobiologica Sinica
基金
国家重大基础研究计划973计划项目(2004CB117401)资助
