title: Genome-wide microarray screening for Bombyx mori genes related to transmitting the determination outcome of whether to produce diapause or nondiapause eggs.
abstract: The bivoltine silkworm Bombyx mori (Lepidoptera: Bombycidae) exhibits a maternally controlled embryonic diapause. Maternal silkworms decide whether to lay diapause or nondiapause eggs depending on environmental factors such as the temperature and photoperiod during the egg and larval stages, and then induce diapause eggs during the pupal stage. However, little is known about the molecular mechanism that conveys the outcome of whether to produce diapause or nondiapause eggs from the egg or larval stages to the pupal stage. This study used microarray analysis to investigate differentially expressed genes in the larval brains of diapause- and nondiapause-egg producers, to which bivoltine silkworms were destined by thermal or photic stimulation during the egg stage. The cytochrome P450 18a1 and Krüppel homolog 1 genes were upregulated in producers of diapause eggs compared with those of nondiapause eggs under both experimental conditions. Cytochrome P450 18a1 encodes a key enzyme for steroid hormone inactivation and Krüppel homolog 1 is an early juvenile hormone-inducible gene that mediates the repression of metamorphosis. The upregulation of these genes during the larval stage might be involved in the signaling pathway that transmits information about the diapause program from the egg stage to the pupal stage in the silkworm.
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors.forename: Shion
authors.initials: S
authors.lastname: Akitomo
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Egi
authors.affiliation: Insect Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences (NIAS), Tsukuba, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Insect Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences (NIAS), Tsukuba, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Suetsugu
authors.affiliation: Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
authors.forename: Katsutaka
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Sakamoto
mesh_terms: D000818:Animals; D012831:Bombyx / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D001921:Brain / Q000254:growth & development / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D064666:Diapause, Insect / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D049750:Genome, Insect; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010058:Oviposition / Q000235:genetics; D010063:Ovum; D017440:Photoperiod; D011679:Pupa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013696:Temperature
chemical_list: D003577:Cytochrome P-450 Enzyme System
keywords: Krüppel homolog 1; cytochrome P450 18a1; silkworm