Purification and cloning of type A/B hnRNP proteins involved in transcriptional activation from the Rat spi 2 gene GAGA box

Biol Chem. 2000 Nov;381(11):1031-40. doi: 10.1515/BC.2000.127.

Abstract

The GAGA box of the rat serine protease inhibitor 2 (spi 2) genes not only acts as a basal promoter element, but also mediates transcriptional activation by growth hormone and interleukin-6. The GAGA box is separated from the TATA box by only 12 bp, and this close association is required for efficient transcription. Hence, the GAGA box may influence transcription efficiency through interactions between GAGA box binding proteins and some components of the RNA polymerase II complex. Here we report the cloning of two GAGA box-binding proteins termed p38 and p40, that belong to the type A/B heterogeneous nuclear ribonucleoprotein subgroup. GAGA box mutations that diminish the affinity for p38 and p40 decrease basal and GH-induced reporter gene expression. Furthermore, nuclear extracts depleted of p38 and p40 can no longer support GAGA box-dependent in vitro transcription. Therefore, two polypeptides previously assigned to a family of RNA processing proteins also act as DNA-binding, promoter-specific transcription factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • CCAAT-Binding Factor / genetics
  • Cell-Free System
  • Cloning, Molecular
  • Enhancer Elements, Genetic
  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Humans
  • Liver / metabolism
  • Mice
  • Molecular Sequence Data
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Promoter Regions, Genetic*
  • RNA-Binding Proteins / genetics
  • Rats
  • Ribonucleoproteins / genetics*
  • Ribonucleoproteins / isolation & purification
  • Ribonucleoproteins / metabolism
  • Sequence Homology, Amino Acid
  • Serpins*
  • Transcription, Genetic
  • Transcriptional Activation*

Substances

  • CCAAT-Binding Factor
  • HNRNPAB protein, human
  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B
  • Heterogeneous-Nuclear Ribonucleoproteins
  • LOC299282 protein, rat
  • Nuclear Proteins
  • RNA-Binding Proteins
  • Ribonucleoproteins
  • Serpina3k protein, mouse
  • Serpins