title: piRNA-mediated transposon regulation and the germ-line mutation rate in Drosophila melanogaster males.
abstract: Transposons, especially retrotransposons, are abundant in the genome of Drosophila melanogaster. These mobile elements are regulated by small RNAs that interact with the Piwi family of proteins-the piwi-interacting or piRNAs. The Piwi proteins are encoded by the genes argonaute3 (ago3), aubergine (aub), and piwi. Heterochromatin Protein 1 (HP1), a chromatin-organizing protein encoded by the Suppressor of variegation 205 [Su(var)205] gene, also plays a role in this regulation. To assess the mutational impact of weakening the system for transposon regulation, we measured the frequency of recessive X-linked lethal mutations occurring in the germ lines of males from stocks that were heterozygous for mutant alleles of the ago3, aub, piwi, or Su(var)205 genes. These mutant alleles are expected to deplete the wild-type proteins encoded by these genes by as much as 50%. The mutant alleles of piwi and Su(var)205 significantly increased the X-linked lethal mutation frequency, whereas the mutant alleles of ago3 did not. An increased mutation frequency was also observed in males from one of two mutant aub stocks, but this increase may not have been due to the aub mutant. The increased mutation frequency caused by depleting Piwi or HP1suggests that chromatin-organizing proteins play important roles in minimizing the germ-line mutation rate, possibly by stabilizing the structure of the heterochromatin in which many transposons are situated.
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA. Electronic address: simmo004@umn.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Simmons
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Peterson
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Thorp
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA.
authors.forename: Jared T
authors.initials: JT
authors.lastname: Buschette
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA.
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: DiPrima
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Harter
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN 55108-1095, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Skolnick
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D004251:DNA Transposable Elements; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics*; D018095:Germ-Line Mutation; D008297:Male; D010448:Peptide Initiation Factors / Q000235:genetics; D034741:RNA, Small Interfering / Q000502:physiology*
chemical_list: C518392:AGO3 protein, Drosophila; D060565:Argonaute Proteins; D002868:Chromosomal Proteins, Non-Histone; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D010448:Peptide Initiation Factors; D034741:RNA, Small Interfering; C000716867:Su(var)205 protein, Drosophila; C436124:aub protein, Drosophila; C452193:heterochromatin protein 1, Drosophila; C116498:piwi protein, Drosophila; D000090266:Chromobox Protein Homolog 5
keywords: Chromatin organization; Mutation rate; Transposons; piRNA