Structure and expression analysis of the cecropin-E gene from the silkworm, Bombyx mori.
Cecropins belong to the antibacterial peptides family and are induced after injection of bacteria or their cell-wall components. By silkworm cDNA microarray analysis, a novel type of Cecropin family gene was identified as a cDNA up-regulated in early embryo, 1 day after oviposition. The cDNA isolated was 394 bp with 198 ORF translating 65 amino acids, encoding BmCecropin-E (BmCec-E). Using Southern hybridization and genome search analysis, the number of BmCec-E gene was estimated to be at least two per haploid, which consisted of two exons, as in other Cecropin family members. BmCec-E mRNA was expressed transiently 1 day after egg-laying (AEL, germ-band formation stage), and was specifically expressed in the degenerating intestine during the pre-pupal and pupal stages, unlike other Cecropin family genes. Immune challenge analysis showed that BmCec-E gene expression was more strongly induced by Escherichia coli (gram-negative) than by Micrococus luteus (gram-positive), and not by virus injection. By bacterial challenge, expression of BmCec-E mRNA was induced 12 h after injection, and was maintained for 24 h. Expression of BmCec-E after immune challenge was observed strongly in excretory organs, such as hindgut and malphigian, slightly in fat body, skin, and midgut.
Hong
Sun-Mee
SM
Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki, Fukuoka, Japan.
Kusakabe
Takahiro
T
Lee
Jae-Man
JM
Tatsuke
Tsuneyuki
T
Kawaguchi
Yutaka
Y
Kang
Min-Wook
MW
Kang
Seok-Woo
SW
Kim
Kyung-A
KA
Nho
Si-Kab
SK
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000737:chemistry / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D054807:Cecropins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental; D016678:Genome / Q000235:genetics; D019476:Insect Proteins; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D054807:Cecropins; D019476:Insect Proteins