Vaccinia NPH-I, a DExH-box ATPase, is the energy coupling factor for mRNA transcription termination. Academic Article uri icon

Overview

abstract

  • Vaccinia virus RNA polymerase terminates transcription in response to a specific signal UUUUUNU in the nascent RNA. Transduction of this signal to the elongating polymerase requires a trans-acting viral termination factor (VTF/capping enzyme), and is coupled to the hydrolysis of ATP. Recent studies suggest that ATP hydrolysis is catalyzed by a novel termination protein (factor X), which is tightly associated with the elongation complex. Here, we identify factor X as NPH-I (nucleoside triphosphate phosphohydrolase-I), a virus-encoded DNA-dependent ATPase of the DExH-box family. We report that NPH-I serves two roles in transcription (1) it acts in concert with VTF/CE to catalyze release of UUUUUNU-containing nascent RNA from the elongation complex, and (2) it acts by itself as a polymerase elongation factor to facilitate readthrough of intrinsic pause sites. A mutation (K61A) in the GxGKT motif of NPH-I abolishes ATP hydrolysis and eliminates the termination and elongation factor activities. Related DExH proteins may have similar roles at postinitiation steps during cellular mRNA synthesis.

publication date

  • February 15, 1998

Research

keywords

  • Acid Anhydride Hydrolases
  • Adenosine Triphosphatases
  • RNA, Messenger
  • Terminator Regions, Genetic
  • Transcription, Genetic
  • Vaccinia virus

Identity

PubMed Central ID

  • PMC316528

Scopus Document Identifier

  • 0032519829

Digital Object Identifier (DOI)

  • 10.1101/gad.12.4.538

PubMed ID

  • 9472022

Additional Document Info

volume

  • 12

issue

  • 4