CCAAT-binding factor NF-Y and RFX are required for in vivo assembly of a nucleoprotein complex that spans 250 base pairs: the invariant chain promoter as a model - PubMed (original) (raw)

CCAAT-binding factor NF-Y and RFX are required for in vivo assembly of a nucleoprotein complex that spans 250 base pairs: the invariant chain promoter as a model

M W Linhoff et al. Mol Cell Biol. 1997 Aug.

Abstract

The events that lead to promoter accessibility within chromatin are not completely understood. The invariant chain (Ii) promoter was used as a model to determine the contribution of different DNA-binding factors in establishing occupancy of a complex promoter. Gamma interferon induction of the Ii promoter requires the cooperation of multiple cis elements including distal S, X, and Y/CCAAT elements along with proximal GC and Y/CCAAT elements. The heteromeric transcription factor NF-Y binds to both Y/CCAAT elements. Genomic footprinting was used to analyze in vivo protein-DNA contacts for integrated Ii promoters bearing mutations in each element. The results reveal a hierarchy of transcription factor loading with NF-Y binding to the distal Y/CCAAT element being required for establishing protein-DNA interactions over the entire 250 bp analyzed. Mutation of the X box disrupts binding primarily at the adjacent Y/CCAAT element along with a lesser effect on GC box binding. Importantly, this finding is verified with a cell line which lacks a functional X-box-binding factor, RFX, providing physiological validity for the strategy described here. Mutation of both the S element and the GC box results in either no or little effect on transcription factor binding. However, mutation of the proximal Y/CCAAT element disrupts binding to the adjacent GC box and partially reduces binding in the distal S/X/Y domain. The crucial role for NF-Y in establishing promoter occupancy may be related to its histone fold motif, the essential component for assembling nucleosome-like structures.

PubMed Disclaimer

Similar articles

Cited by

References

    1. EMBO J. 1994 Sep 1;13(17):4042-53 - PubMed
    1. Cell. 1994 Apr 8;77(1):5-8 - PubMed
    1. Biotechniques. 1994 Jul;17(1):36, 38, 40 - PubMed
    1. J Exp Med. 1995 Feb 1;181(2):765-7 - PubMed
    1. Proc Natl Acad Sci U S A. 1995 Feb 28;92(5):1624-8 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources