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Preferential codon usage and two types of repetitive motifs in the fibroin gene of the Chinese oak silkworm, Antheraea pernyi
Author(s) -
Yukuhiro K.,
Kanda T.,
Tamura T.
Publication year - 1997
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1046/j.1365-2583.1997.00161.x
Subject(s) - antheraea pernyi , fibroin , bombyx mori , biology , gene , silk , genetics , stop codon , alanine , amino acid , materials science , composite material
In this paper we describe the peculiar structures and preferential codon usage found in wild silkworm fibroin genes. We determined a 1350 bp nucleotide sequence from the Chinese oak silkworm,Antheraea pernyi. The deduced amino acid sequence was partitioned into thirteen polyalanine‐containing repetitive motifs, which was one of the characteristics ofAntheraeafibroins. Eleven of these arrays can be classified into two types of motifs depending on difference in amino acid sequences following polyalanine. Repetitive motifs structurally similar to those ofA. pernyiwere detected in a homologue of the Japanese oak silkworm,Antheraea yamamai. The most remarkable feature of this study was preferential codon usage, especially seen in alanine synonymous codons within both homologues ofAntheraea: isocodon GCA most frequently occurred in alanine isocodons. In contrast, GCU isocodon was the most abundant inBombyx morifibroin heavy chain that lacks polyalanine arrays. This result strongly suggests different modes of selective constraint between the two types of fibroin gene. The similar finding that GCA isocodon was most frequent in two dragline silk sequences of the spider,Nephila clavipes, is consistent with our results because of the repetitive polyalanine‐containing arrays seen in spider dragline silk.