Characterization of the @entity3392 XXXX gene promoter: Its regulation of cardiac-specific expression and skeletal muscle-specific repression.

@entity72878 @entity1 @entity53218 @entity72879 @entity21505 @entity299 @entity43669 @entity3392 @entity4297
UNASSIGNED: @entity3392 connexin 36.7 ( @entity72878 /ecx) has been identified as a key molecule in the early stages of heart development in this species. A defect in @entity72878 causes severe @entity4297 due to the downregulation of @entity21505 expression, a result which resembles @entity299 in @entity1 . It has been shown that @entity72878 is expressed specifically in early developing @entity299 . However, the regulatory mechanism for the cardiac-restricted expression of @entity72878 remains to be elucidated. In this study we isolated the 5'-flanking promoter region of the @entity72878 gene and characterized its promoter activity in @entity3392 embryos. Deletion analysis showed that a 316-bp upstream region is essential for cardiac-restricted expression. This region contains four @entity53218 elements, the proximal two of which are responsible for promoter activation in the embryonic heart and serve as binding sites for @entity53218 . When @entity53218 , @entity43669 and @entity72879 were simultaneously knocked down, the promoter activity was significantly decreased. Moreover, the deletion of the region between -316 and -133bp led to EGFP expression in the embryonic trunk muscle. The distal two @entity53218 and A/T-rich elements in this region act as repressors of promoter activity in skeletal muscle. These results suggest that @entity72878 expression is directed by cardiac promoter activation via the two proximal @entity53218 elements as well as by skeletal muscle-specific promoter repression via the two distal @entity53218 elements.
