Ubl4b, an X-derived retrogene, is specifically expressed in post-meiotic germ cells in mammals

Gene Expr Patterns. 2007 Jan;7(1-2):131-6. doi: 10.1016/j.modgep.2006.06.002. Epub 2006 Jun 14.

Abstract

Post-translational modification by ubiquitin and ubiquitin-related proteins plays critical roles in protein degradation and in regulation of essential cellular processes. In mammals, transcription grinds to a halt during late spermiogenesis due to compaction of the spermatid genome, which creates a special need for robust post-transcriptional regulation. Here, we report the finding of a novel mouse ubiquitin-like protein, UBL4B. Ubl4b is a testis-specific autosomal gene. Ubl4b lacks introns and evidently arose from an X-linked intron-bearing housekeeping gene, Ubl4a, by retroposition during mammalian evolution. While Ubl4a is expressed throughout spermatogenesis, Ubl4b is restricted to post-meiotic germ cells. Ubl4a is highly conserved, but Ubl4b has undergone rapid evolution and may have evolved new functions. Our data suggest that evolution of Ubl4b is not due to meiotic sex chromosome inactivation (MSCI). Alternatively, origination of Ubl4b was due to MSCI, but Ubl4b eventually evolved to be restricted to post-meiotic germ cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • DNA Primers / genetics
  • Evolution, Molecular
  • Gene Expression Regulation, Developmental
  • Humans
  • Male
  • Mammals / genetics
  • Marsupialia / genetics
  • Meiosis / genetics
  • Mice
  • Phylogeny
  • Retroelements
  • Spermatogenesis / genetics*
  • Ubiquitins / genetics*
  • X Chromosome / genetics*
  • X Chromosome Inactivation

Substances

  • DNA Primers
  • Retroelements
  • Ubiquitins