title: Identification and characterization of Polycomb group genes in the silkworm, Bombyx mori.
abstract: Polycomb group (PcG) proteins are involved in chromatin modifications for maintaining gene repression that play important roles in the regulation of gene expression, tumorigenesis, chromosome X-inactivation, and genomic imprinting in Drosophila melanogaster, mammals, and even plants. To characterize the orthologs of PcG genes in the silkworm, Bombyx mori, 13 candidates were identified from the updated silkworm genome sequence by using the fruit fly PcG genes as queries. Comparison of the silkworm PcG proteins with those from other insect species revealed that the insect PcG proteins shared high sequence similarity. High-level expressions of all the silkworm PcG genes were maintained through day 2 to day 7 of embryogenesis, and tissue microarray data on day 3 of the fifth instar larvae showed that their expression levels were relatively low in somatic tissues, except for Enhancer of zeste (E(Z)). In addition, knockdown of each PRC2 component, such as E(Z), Extra sex combs (ESC), and Suppressor of zeste 12 (SU(Z)12), considerably decreased the global levels of H3K27me3 but not of H3K27me2. Taken together, these results suggest that insect PcG proteins are highly conserved during evolution and might play similar roles in embryogenesis.
authors.affiliation: Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan.
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Li
authors.forename: Tsuneyuki
authors.initials: T
authors.lastname: Tatsuke
authors.forename: Kosuke
authors.initials: K
authors.lastname: Sakashita
authors.forename: Li
authors.initials: L
authors.lastname: Zhu
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mon
authors.forename: Jae Man
authors.initials: JM
authors.lastname: Lee
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kusakabe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D002460:Cell Line; D047108:Embryonic Development / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D017344:Genes, Insect / Q000235:genetics*; D006657:Histones / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D008938:Mitosis / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D063146:Polycomb-Group Proteins; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
chemical_list: D006657:Histones; D019476:Insect Proteins; D063146:Polycomb-Group Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins