Abstract: hKv4.3 is the main molecular basis of transient outward K⁺ current(I_to). Its expression is found in abundance in heart and brain, but with no detectable expression in other tissue. In order to define the gene regulation of hKv4.3 expression, we cloned the sequence(+2—+160, S160) in the 5'UTR of hKv4.3 gene into the report plasmid, and it was transiently expressed. It was found that S160 repressed the activity of promoter of hKv4.3 and SV40, moreover, its repression function with position-specificity but without orientation-specificity. Through the analysis of deletion mutant, we found an repressor element S(GAGGGGTTAA) locating in the downstream region(+20—+30 bp) of TSS. We analyzed mRNA quantity with RT-PCR method, and think that the repressor element S maybe represses the expression in translation level.

Key words: hKv4.3 gene, Silencer, Promoter, Deletion mutation