Identification of a site that mediates transcriptional response of the human beta-actin gene to serum factors.

In quiescent fibroblasts, low-level transcription of the beta-actin gene occurs, and it is rapidly induced by growth factors in serum. Deletion analysis of the 5' upstream region of the human beta-actin gene using a CAT assay showed that the region between +765 and +783 downstream from the cap site, which had enhancer activity in growing NIH3T3 cells, also acted as a serum-response element in quiescent cells. The data suggest that the 19-bp element acts positively as a serum response element. This sequence contains a CC(A/T)6GG sequence which is found in the promoter region of many cytoskeletal and muscle-specific actin genes.