title: Dicer-related drh-3 gene functions in germ-line development by maintenance of chromosomal integrity in Caenorhabditis elegans.
abstract: In the course of systematic RNA interference (RNAi)-based screens with helicase-like genes in Caenorhabditis elegans, we have identified the drh-3(D2005.5) gene as a candidate gene for protection against X-ray irradiation. This gene encodes a novel RNA helicase-like protein that is similar to two nematode Dicer-related helicases (DRH). Here, we have showed the increased expression of drh-3 transcripts during maturation of larvae to adults, and characterized the phenotype of drh-3-interferred nematodes using feeding RNAi method. RNAi-mediated depletion of the drh-3 transcripts caused embryonic lethality of F1 progeny and temperature-sensitive reproductive capacity but did not affect the nematode life span. F1 progeny from drh-3(RNAi) animals exhibited increased lethality after X-ray irradiation or exposure to camptothecin. In drh-3(RNAi) worms, aggregated chromosomes were observed in diakinesis oocyte nuclei. In developing early zygotic embryos from drh-3(RNAi) worms, abnormally segregated chromosomes were observed and embryonic development was largely arrested at the mid-stages of embryogenesis. Finally, examination of checkpoint responses in mitotic germ cells with regards to replication arrest by hydroxyurea and X-ray-induced DNA damage suggested that both checkpoints function normally under these genotoxic stress conditions. Taken together, these results indicate that the drh-3 gene is essential for the development of germ-lines by maintaining chromosomal integrity in C. elegans.
authors.affiliation: Division of Life Science and Biotechnology, Department of Ecological Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nakamura
authors.forename: Rumi
authors.initials: R
authors.lastname: Ando
authors.forename: Taro
authors.initials: T
authors.lastname: Nakazawa
authors.forename: Takuro
authors.initials: T
authors.lastname: Yudazono
authors.forename: Naoko
authors.initials: N
authors.lastname: Tsutsumi
authors.forename: Naoki
authors.initials: N
authors.lastname: Hatanaka
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Ohgake
authors.forename: Fumio
authors.initials: F
authors.lastname: Hanaoka
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Eki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics* / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D002875:Chromosomes / Q000502:physiology*; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000254:growth & development*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D010641:Phenotype; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D020539:Sequence Analysis, Protein; D015053:Zygote / Q000378:metabolism