Enhanced activation of the human histone H2B promoter by an Oct-1 variant generated by alternative splicing

J Biol Chem. 1993 Nov 25;268(33):25026-32.

Abstract

POU homeodomain proteins are important regulators of ubiquitous as well as tissue-specific transcription. These factors include the broadly expressed octamer motif-binding protein Oct-1 and the related cell-specifically expressed protein Oct-2. These two proteins differ in the types of octamer motif-containing promoters they preferentially activate; Oct-1 can activate RNA polymerase II transcription from a small nuclear RNA promoter better than Oct-2, which can better activate an mRNA-type promoter. We describe a variant Oct-1-encoding cDNA resulting from two separate alternate splices of the human oct-1 primary transcript; these alternate splices were present in all cell lines tested. This cDNA encodes an amino-terminally and carboxyl-terminally truncated form of Oct-1, called Oct-1B, which retains the DNA-binding POU domain and acquires a unique 12-amino acid carboxyl-terminal extension. In a transient expression assay, Oct-1B displayed an enhanced ability compared to the larger form of Oct-1 (called Oct-1A in this report) to activate the human histone H2B promoter, an mRNA-type promoter where a natural octamer motif is involved in cell cycle dependent transcription. Thus, the ability of Oct-1 related proteins to activate a natural regulatory target can be influenced by alternative splicing.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alternative Splicing*
  • Amino Acid Sequence
  • Base Sequence
  • Cells, Cultured
  • DNA
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Histones / genetics*
  • Host Cell Factor C1
  • Humans
  • Molecular Sequence Data
  • Octamer Transcription Factor-1
  • Promoter Regions, Genetic*
  • Protein Biosynthesis
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic*

Substances

  • DNA-Binding Proteins
  • HCFC1 protein, human
  • Histones
  • Host Cell Factor C1
  • Octamer Transcription Factor-1
  • POU2F1 protein, human
  • RNA, Messenger
  • Transcription Factors
  • DNA