Elevated expression of Piwi and piRNAs in ovaries of triploid crucian carp

Mol Cell Endocrinol. 2014 Mar 5;383(1-2):1-9. doi: 10.1016/j.mce.2013.11.019. Epub 2013 Dec 4.

Abstract

Increasing piRNAs provide RNA-interference pathways to regulate transposons and gene expression in germline cells. We demonstrate that Piwi transcripts are exclusively expressed in adult testes and ovaries in teleosts, with triploids showing the highest Piwi expression in the ovaries. Studies in vivo and in vitro showed that hCG and E2 treatment suppressed Piwi expression. We further cloned 200 small RNAs in the three kinds of fish. Seven piRNAs were obtained from all the three different ploidy fishes. During ovulation, five piRNAs showed significantly higher expression in the ovaries of sterile triploids than fertile diploids and tetraploids. Furthermore, E2 suppressed the expression of the six piRNAs at different levels in vivo and in vitro. The present study bridges the gap between the HPG axis and Piwi-piRNA pathway by suggesting that a dysfunctional HPG axis abrogated the piRNA suppression in triploid fish.

Keywords: HPG axis; Piwi; Tetraploid; Triploid; piRNAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Carps / genetics*
  • Chorionic Gonadotropin / pharmacology
  • Dinoprostone / pharmacology
  • Female
  • Gene Expression Regulation
  • Hypothalamo-Hypophyseal System / drug effects
  • Hypothalamo-Hypophyseal System / metabolism
  • Molecular Sequence Data
  • Ovary / drug effects
  • Ovary / metabolism*
  • Ploidies*
  • RNA, Small Interfering / genetics*
  • RNA, Small Interfering / metabolism
  • Reproduction / genetics*
  • Sequence Alignment
  • Signal Transduction

Substances

  • Chorionic Gonadotropin
  • RNA, Small Interfering
  • Dinoprostone