title: Transgenic Expression of the piRNA-Resistant Masculinizer Gene Induces Female-Specific Lethality and Partial Female-to-Male Sex Reversal in the Silkworm, Bombyx mori.
abstract: In Bombyx mori (B. mori), Fem piRNA originates from the W chromosome and is responsible for femaleness. The Fem piRNA-PIWI complex targets and cleaves mRNAs transcribed from the Masc gene. Masc encodes a novel CCCH type zinc-finger protein and is required for male-specific splicing of B. mori doublesex (Bmdsx) transcripts. In the present study, several silkworm strains carrying a transgene, which encodes a Fem piRNA-resistant Masc mRNA (Masc-R), were generated. Forced expression of the Masc-R transgene caused female-specific lethality during the larval stages. One of the Masc-R strains weakly expressed Masc-R in various tissues. Females heterozygous for the transgene expressed male-specific isoform of the Bombyx homolog of insulin-like growth factor II mRNA-binding protein (ImpM) and Bmdsx. All examined females showed a lower inducibility of vitellogenin synthesis and exhibited abnormalities in the ovaries. Testis-like tissues were observed in abnormal ovaries and, notably, the tissues contained considerable numbers of sperm bundles. Homozygous expression of the transgene resulted in formation of the male-specific abdominal segment in adult females and caused partial male differentiation in female genitalia. These results strongly suggest that Masc is an important regulatory gene of maleness in B. mori.
authors: Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan.
authors: Hiroki
authors: H
authors: Sakai
authors: Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, Ibaraki 305-8634, Japan.
authors: Megumi
authors: M
authors: Sumitani
authors: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
authors: Yasuhiko
authors: Y
authors: Chikami
authors: Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
authors: Kensuke
authors: K
authors: Yahata
authors: Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, Ibaraki 305-8634, Japan.
authors: Keiro
authors: K
authors: Uchino
authors: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Takashi
authors: T
authors: Kiuchi
authors: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Susumu
authors: S
authors: Katsuma
authors: Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan.
authors: Fugaku
authors: F
authors: Aoki
authors: Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, Ibaraki 305-8634, Japan.
authors: Hideki
authors: H
authors: Sezutsu
authors: Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan.
authors: Masataka G
authors: MG
authors: Suzuki
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D012831:Bombyx / Q000235:genetics* / Q000254:growth & development; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis / Q000235:genetics*; D008297:Male; D010053:Ovary / Q000254:growth & development / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics; D034741:RNA, Small Interfering / Q000096:biosynthesis / Q000235:genetics*; D012730:Sex Chromosomes / Q000235:genetics; D019849:Sex Determination Processes / Q000235:genetics*; D013737:Testis / Q000254:growth & development / Q000378:metabolism; D014819:Vitellogenins / Q000096:biosynthesis / Q000235:genetics
chemical_list: C442431:Bmdsx protein, Bombyx mori; D004268:DNA-Binding Proteins; D019476:Insect Proteins; D034741:RNA, Small Interfering; D014819:Vitellogenins; D007335:Insulin-Like Growth Factor II