RNA polymerase II interacts with the Hspa1b promoter in mouse epididymal spermatozoa

Reproduction. 2009 Jun;137(6):923-9. doi: 10.1530/REP-09-0015. Epub 2009 Mar 31.

Abstract

The Hspa1b (Hsp70.1) gene is one of the first genes expressed after fertilization, with expression occurring during the minor zygotic genome activation (ZGA) in the absence of stress. This expression can take place in the male pronucleus as early as the one-cell stage of embryogenesis. The importance of HSPA1B for embryonic viability during times of stress is supported by studies showing that depletion of this protein results in a significant reduction in embryos developing to the blastocyte stage. Recently, we have begun addressing the mechanism responsible for allowing expression of Hspa1b during the minor ZGA and found that heat shock transcription factor (HSF) 1 and 2 bind the Hspa1b promoter during late spermatogenesis. In this report, we have extended those studies using western blots and chromatin immunoprecipitation assays and found that RNA polymerase II (Pol II) is present in epididymal spermatozoa and bound to the Hspa1b promoter. These present results, in addition to our previous results, support a model in which the binding of HSF1, HSF2, SP1, and Pol II to the promoter of Hspa1b would allow the rapid formation of a transcription-competent state during the minor ZGA, thereby allowing Hspa1b expression.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Binding Sites
  • Blotting, Western
  • Cell Nucleus / enzymology
  • Chromatin Immunoprecipitation
  • Epididymis / enzymology*
  • Gene Expression Regulation, Developmental
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / metabolism*
  • Male
  • Mice
  • Promoter Regions, Genetic*
  • RNA Polymerase II / metabolism*
  • Spermatozoa / enzymology*

Substances

  • HSP70 Heat-Shock Proteins
  • heat-shock protein 70.1
  • RNA Polymerase II