STUDY ON TRANSCRIPTION FACTORS REGULATING GENE EXPRESSION IN SEA URCHIN EMBRYOS

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The present research project has been undertaken to elucidate a cascade of transcription factors related to temporally and spatially regulated expression of genes during early development of sea urchin. Results obtained during the research period for this grant are as follows.(1) A procedure to introduce exogenous DNA into sea urchin eggs by a particle gun has been developed.(2) Temporal expression of the Ars gene is regulated by two distinct cisactive elements in its promoter region (from -252 to +38bp), though level of transcription initiated by these elements alone is very low and declines rapidly.(3) GGATTA sequences (known as binding sites for transcription factor 0tx) in the first intron of the Ars gene act as a transcriptional enhancer of this gene. Two distinct cDNAs (Hp0tx_E and Hp0tx_L) encoding Hp0tx have been cloned. Hp0tx_E is a maternal factor and suppresses the Ars gene transcription, while Hp0tx_L is produced in hatched blastulae and activates the Ars gene transcription. Two cDNAs are produced from the same gene by alternative splicing.(4) It is found that the region from -2686 to -2113bp of the Ars gene acts as an transcriptional insulator that prevents the Ars gene to be transcribed under the influence of promoter of the gene located in a closely vicinity.