Histone-derived piRNA biogenesis depends on the ping-pong partners Piwi5 and Ago3 in Aedes aegypti

Nucleic Acids Res. 2017 May 5;45(8):4881-4892. doi: 10.1093/nar/gkw1368.


The piRNA pathway is of key importance in controlling transposable elements in most animal species. In the vector mosquito Aedes aegypti, the presence of eight PIWI proteins and the accumulation of viral piRNAs upon arbovirus infection suggest additional functions of the piRNA pathway beyond genome defense. To better understand the regulatory potential of this pathway, we analyzed in detail host-derived piRNAs in A. aegypti Aag2 cells. We show that a large repertoire of protein-coding genes and non-retroviral integrated RNA virus elements are processed into genic piRNAs by different combinations of PIWI proteins. Among these, we identify a class of genes that produces piRNAs from coding sequences in an Ago3- and Piwi5-dependent fashion. We demonstrate that the replication-dependent histone gene family is a genic source of ping-pong dependent piRNAs and that histone-derived piRNAs are dynamically expressed throughout the cell cycle, suggesting a role for the piRNA pathway in the regulation of histone gene expression. Moreover, our results establish the Aag2 cell line as an accessible experimental model to study gene-derived piRNAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aedes / genetics*
  • Animals
  • Argonaute Proteins / genetics*
  • DNA Transposable Elements / genetics
  • Drosophila Proteins / genetics
  • Gene Expression Regulation
  • Histones / genetics*
  • RNA, Small Interfering / biosynthesis
  • RNA, Small Interfering / genetics*


  • AGO3 protein, Drosophila
  • Argonaute Proteins
  • DNA Transposable Elements
  • Drosophila Proteins
  • Histones
  • RNA, Small Interfering