title: DNA replication events during larval silk gland development in the silkworm, Bombyx mori.
abstract: The silk gland is an important organ in silkworm as it synthesizes silk proteins and is critical to spinning. The genomic DNA content of silk gland cells dramatically increases 200-400 thousand times for the larval life span through the process of endomitosis. Using in vitro culture, DNA synthesis was measured using BrdU labeling during the larval molt and intermolt periods. We found that the cell cycle of endomitosis was activated during the intermolt and was inhibited during the molt phase. The anterior silk gland, middle silk gland, and posterior silk gland cells asynchronously exit the endomitotic cycle after day 6 in 5th instar larvae, which correlated with the reduced expression of the cell cycle-related cdt1, pcna, cyclin E, cdk2 and cdk1 mRNAs in the wandering phase. Additional starvation had no effect on the initiation of silk gland DNA synthesis of the freshly ecdysed larvae.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, PR China.
authors.forename: Chun-Dong
authors.initials: CD
authors.lastname: Zhang
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Li
authors.forename: Xiang-Yun
authors.initials: XY
authors.lastname: Chen
authors.forename: Mao-Hua
authors.initials: MH
authors.lastname: Huang
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Cui
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Pan
authors.forename: Cheng
authors.initials: C
authors.lastname: Lu
mesh_terms: D000825:Animal Structures / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D000818:Animals; D012831:Bombyx / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D002453:Cell Cycle; D004261:DNA Replication; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018978:Molting; D047011:Silk / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D047011:Silk