The 30‐kDa rat liver transcription factor nuclear factor 1 binds the rat growth‐hormone proximal silencer

Abstract

Transcription of the gene encoding rat growth hormone is under the influence of cis‐acting negative regulatory elements termed silencers. We showed previously that one such element, designated the rat growth hormone proximal silencer‐1 site, binds a nuclear protein, the nuclear‐factor‐1‐like protein that is probably a member of the CAAT transcription factor/nuclear‐factor‐1 (CTF/NF‐I) family of transcription factors. This nuclear protein possesses DNA‐binding activity as well as biochemical properties similar to those reported for the 30‐kDa rat liver form of nuclear factor 1 (NF1‐L). Results from both gel mobility supershift assays and Western‐blot analyses, performed in combination with a polyclonal antibody directed against the DNA‐binding domain of NF1‐L, indicated that rat liver nuclear factor 1 might indeed correspond to one of the transcription factors interacting with the rat growth‐hormone proximal silencer element. Further experiments using gel mobility shift assays also indicated that, as for NF1‐L, multiple proteins among the 52–66‐kDa CTF/NF‐I isoforms from human HeLa cells also possess the ability to bind the rat growth‐hormone silencer. Copyright © 1994, Wiley Blackwell. All rights reserved