An upstream region of the H2AZ gene promoter modulates promoter activity in different cell types

摘要

Human H2AZ gene promoter fragments that included sequences upstream from the core promoter resulted in decreased activity of reporter constructs transfectcd into several huinnn cell lines, but increased activity in the undiffcrcntiatcd human embryonal carcinoma cell line Tera-2. Differentiation of Tera-2 cells in media containing retinoic acid restored the ability of the upstream region to downregulate H2AZ gene promoter activity. Levels of endogenous H2AZ niRNA were also found to be 2.5-lbld higher in undilTerenti-ated Tera-2 cells than in clilTerentiated Tera-2 cells. A 128 bp region located 234 to 361 bp upstream from the transcription start site of the H2AZ gene was found to be responsible for the modulation of reporter activity. The upstream region also functioned similarly when removed from the H2AZ gene promoter and inserted upstream of the SV40 promoter in reporter constructs. Gel mobility shift studies of fragments of this region revealed two sequence elements, CTCCTCC ami CACGTO, that bound nuclear factors in vitro.