SCREENING OF DIFFERENTIALLY EXPRESSED GENES AT GASTRULA STAGE DURING EMBRYOGENESIS OF CARASSIUS AURATUS GIBELIO

Embryogenesis is a progressive and complicated process that is regulated by differential gene activity. In order to identify some differentially expressed genes in early embryogenesis,two kinds of SMART cDNAs were respectively synthesized frommature eggs and gastrula embryos of Carassius auratus gibelio,and the gastrula embryo SMART cDNA library was constructed.Following this program,131 positive clones were screenedfrom about 1500 clones of the gastrula embryo SMARTcDNA library bytwo rounds of dotblot differential hybridizations using the synthesized SMARTcDNAs as probes. Furthermore,58 positive cloneswere selected for sequencing. Searching GenBank by the nucleotide sequences indicated that most of the sequenced cDNAs encoded ribosome proteins and regulators involved in translation and transcription,and some encoded lipoproteins involved in themetabolism of fat. And,some unknown new genes were also identified from the screening. Moreover,we investigated the expression patternsof 6 genes during embryogenesis by RTPCR analysis,and confirmed their differential expression during embryogenesis. Four different expression patterns,such as transcribing again at gastrula based on the maternal products,beginning to transcribe at blastula stage, beginning to transcribe at gastrula stage,and transcribing only during embryogenesis, were revealed inthe analyzed genes. Through this study,we cloned and identified some genes expressed differentially at early stage during embryo2genesis,which will be a solid base for further researches on their functions and regulative mechanisms during embryogenesis.