Identification of a Bombyx collagenous protein with multiple short domains of Gly-Xaa-Yaa repeats: cDNA characterization and regulation of expression.
Using a differential screening strategy, a 2 kb cDNA was isolated from a differentiating Bombyx mori imaginal wing discs library. The available reading frame of 1710 bp specifies a conceptual protein with two distinct regions: a 395 amino acid region corresponding to 105 repetitions of the Gly-Xaa-Yaa triple-helical forming unit arranged in 9 domains of 12-54 residues interspaced by short interruptions of 3-17 residues and a C-terminal domain of 175 amino acids devoided of triplets. These characteristics suggest that the encoded protein is a new member of the collagen superfamily, the first one characterized in Bombyx. Northern blots reveal a unique 7.4 kb mRNA in imaginal wing discs, epidermis and brain. In wing discs, the 7.4 kb transcripts accumulate during the last larval moult and the spinning stage. In vitro studies reveal that this accumulation is dose dependent and detectable within 1 h in response to 20-hydroxyecdysone which acts without de novo protein synthesis. A model of regulation of transcript accumulation with regards to the hormonal level is proposed.
Chareyre
P
P
Université Lyon I, Centre de Génétique Moléculaire et Cellulaire, U.M.R. C.N.R.S. 5534, Villeurbanne, France.
Besson
M T
MT
Fourche
J
J
Bosquet
G
G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003094:Collagen / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary; D004441:Ecdysterone / Q000494:pharmacology; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics; D012333:RNA, Messenger; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution
D018076:DNA, Complementary; D010446:Peptide Fragments; D012333:RNA, Messenger; D004441:Ecdysterone; D003094:Collagen