Open AccessThe Oct-1 POU-Specific Domain Can Stimulate Small Nuclear RNA Gene Transcription by Stabilizing the Basal Transcription Complex SNAPc
Author(s) -
Vivek Mittal,
Michele A. Cleary,
Winship Herr,
Nouria Hernandez
Publication year - 1996
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.16.5.1955
Subject(s) - pou domain , biology , general transcription factor , rna polymerase ii , enhancer , dna binding domain , transcription factor , histone octamer , transcription (linguistics) , binding domain , promoter , microbiology and biotechnology , transcription factor ii a , transcription preinitiation complex , dna binding protein , genetics , binding site , dna , gene , gene expression , chromatin , homeobox , linguistics , philosophy , nucleosome
The RNA polymerase II and III human small nuclear RNA promoters have a common basal element, the proximal sequence element, which binds the TATA box-binding protein-containing complex SNAPc. They also contain an enhancer characterized by a highly conserved octamer sequence, which constitutes a binding site for the broadly expressed POU domain transcription factor Oct-1. The POU domain is a bipartite DNA-binding domain consisting of a POU-homeo (POUH) domain and a POU-specific (POUs) domain joined by a flexible linker. Here, we show that the Oct-1 POU domain but not the related Pit-1 POU domain can facilitate the binding of SNAPc to the proximal sequence element, and activate transcription. The effect is probably mediated by protein-protein contacts, and 1 of 30 amino acid differences between the Oct-1 and Pit-1 POUs domains is the key determinant for the differential interaction with SNAPc and the ability to activate transcription. These results show that a function that is the hallmark of activation domains, namely, recruitment of a basal transcription complex resulting in activation of transcription, can be performed by a DNA-binding domain. In this case, subtle changes between activator DNA-binding domains, as subtle as a single amino acid difference, can profoundly affect interaction with the basal transcription machinery.