Systematic Analysis of the Protein Interaction Network for the Human Transcription Machinery Reveals the Identity of the 7SK Capping Enzyme

Mol Cell. 2007 Jul 20;27(2):262-74. doi: 10.1016/j.molcel.2007.06.027.

Abstract

We have performed a survey of soluble human protein complexes containing components of the transcription and RNA processing machineries using protein affinity purification coupled to mass spectrometry. Thirty-two tagged polypeptides yielded a network of 805 high-confidence interactions. Remarkably, the network is significantly enriched in proteins that regulate the formation of protein complexes, including a number of previously uncharacterized proteins for which we have inferred functions. The RNA polymerase II (RNAP II)-associated proteins (RPAPs) are physically and functionally associated with RNAP II, forming an interface between the enzyme and chaperone/scaffolding proteins. BCDIN3 is the 7SK snRNA methylphosphate capping enzyme (MePCE) present in an snRNP complex containing both RNA processing and transcription factors, including the elongation factor P-TEFb. Our results define a high-density protein interaction network for the mammalian transcription machinery and uncover multiple regulatory factors that target the transcription machinery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Carrier Proteins / chemistry
  • Carrier Proteins / metabolism
  • Cell Line
  • Humans
  • In Vitro Techniques
  • Macromolecular Substances
  • Molecular Sequence Data
  • Nucleotidyltransferases / chemistry
  • Nucleotidyltransferases / genetics
  • Nucleotidyltransferases / metabolism*
  • Protein Interaction Mapping
  • RNA Interference
  • RNA Polymerase II / chemistry
  • RNA Polymerase II / metabolism
  • RNA Processing, Post-Transcriptional
  • Ribonucleoproteins, Small Nuclear / chemistry
  • Ribonucleoproteins, Small Nuclear / metabolism
  • Transcription, Genetic

Substances

  • Carrier Proteins
  • Macromolecular Substances
  • Ribonucleoproteins, Small Nuclear
  • Nucleotidyltransferases
  • RNA Polymerase II
  • mRNA guanylyltransferase