Structural characterization and expression studies of Dby and its homologs in the mouse

J Androl. Sep-Oct 2006;27(5):653-61. doi: 10.2164/jandrol.106.000471. Epub 2006 May 25.

Abstract

In spite of recent evidence showing the importance of DBY (DEAD-box RNA helicase Y) in spermatogenesis in human, the biologic role of its homolog Dby (also known as Ddx3y) in the mouse is less clear. The present study aims at characterizing the molecular structure of Dby and comparing its expression with its X- and autosome-linked homologs in embryonic gonads and developing germ cells in mice. Molecular cloning by rapid amplification of 3'-cDNA ends showed that the Dby gene in the mouse gives rise to 2 transcripts that differ only in the length of the 3'-untranslated region as a consequence of the use of alternative polyadenylation signals. Measurement by quantitative real-time polymerase chain reaction showed that both transcripts were ubiquitously expressed and were present in male germ cells and Sertoli cells. They were more abundant in type A spermatogonia compared with pachytene spermatocytes and round spermatids. Expression of Dby in the embryonic gonad increased from day 10.5 and reached a peak at day 17.5. The expression level of Dby decreased after birth and remained low in adult male gonads. Although the level of expression of Dby was much lower than its X chromosome homolog, Ddx3 (also known as Ddx3x) in all samples examined, the pattern of expression of the 2 genes was comparable. In contrast, their autosomal homolog, D1Pas1(also known as PL10), was predominantly expressed in pachytene spermatocytes and round spermatids. This result is in accord with meiotic sex chromosome inactivation in that Dby and Ddx are replaced in pachytene spermatocytes by their autosomal retroposon. These observations indicate that unlike DBY in humans, the role of Dby in spermatogenesis is less obvious in the mouse and its biologic activity may be replaced by that of Ddx3 and D1Pas1.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • DEAD-box RNA Helicases
  • Gene Expression Regulation
  • Male
  • Mice
  • Minor Histocompatibility Antigens
  • Molecular Sequence Data
  • RNA Helicases / biosynthesis*
  • RNA Helicases / chemistry
  • RNA Helicases / metabolism
  • Sequence Alignment
  • Testis / embryology
  • Testis / metabolism

Substances

  • Minor Histocompatibility Antigens
  • D1Pas1 protein, mouse
  • Ddx3y protein, mouse
  • DEAD-box RNA Helicases
  • Ddx3x protein, mouse
  • RNA Helicases