title: Ras1(CA) overexpression in the posterior silk gland improves silk yield.
abstract: Sericulture has been greatly advanced by applying hybrid breeding techniques to the domesticated silkworm, Bombyx mori, but has reached a plateau during the last decades. For the first time, we report improved silk yield in a GAL4/UAS transgenic silkworm. Overexpression of the Ras1(CA) oncogene specifically in the posterior silk gland improved fibroin production and silk yield by 60%, while increasing food consumption by only 20%. Ras activation by Ras1(CA) overexpression in the posterior silk gland enhanced phosphorylation levels of Ras downstream effector proteins, up-regulated fibroin mRNA levels, increased total DNA content, and stimulated endoreplication. Moreover, Ras1 activation increased cell and nuclei sizes, enriched subcellular organelles related to protein synthesis, and stimulated ribosome biogenesis for mRNA translation. We conclude that Ras1 activation increases cell size and protein synthesis in the posterior silk gland, leading to silk yield improvement.
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Hanfu
authors.initials: H
authors.lastname: Xu
authors.forename: Jinqi
authors.initials: J
authors.lastname: Zhu
authors.forename: Sanyuan
authors.initials: S
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Rong-Jing
authors.initials: RJ
authors.lastname: Jiang
authors.forename: Qingyou
authors.initials: Q
authors.lastname: Xia
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
mesh_terms: D000825:Animal Structures / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D030801:Animals, Genetically Modified; D001835:Body Weight / Q000235:genetics; D012831:Bombyx / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology; D048429:Cell Size; D019476:Insect Proteins / Q000096:biosynthesis* / Q000235:genetics; D007814:Larva / Q000235:genetics / Q000378:metabolism; D009929:Organ Size; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D047011:Silk / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic; D015854:Up-Regulation; D018631:ras Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D019476:Insect Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D047011:Silk; D018631:ras Proteins