RRC ID 11252
Author Meng Y, Katsuma S, Mita K, Shimada T.
Title Abnormal red body coloration of the silkworm, Bombyx mori, is caused by a mutation in a novel kynureninase.
Journal Genes Cells
Abstract Larvae of the body color mutant red blood (rb) of the silkworm, Bombyx mori, display reddish skin whose hemolymph becomes red in air, whereas hemolymphs of normal strains become black during melanization. The irregular coloring was assumed to result from an abnormal accumulation of 3-hydroxykynurenine. However, the gene responsible for the rb phenotype is not yet known. Here, we provide evidence that the rb gene corresponds to a novel bacterial-type kynureninase gene, BmKynu. Kynureninase (KYNU) hydrolyzes kynurenine and 3-hydroxykynurenine to anthranilic acid and 3-hydroxyanthranilic acid, respectively. KYNU has been identified in microorganisms and animals but not in insects. Therefore, BmKynu is the first KYNU gene observed in insects. Our results clearly showed that a point mutation (T102I) in BmKYNU of the rb strain led to a marked decrease in KYNU activity, presumably resulting in abnormal accumulation of 3-hydroxykynurenine. Additionally, linkage analysis indicated that no recombination between rb and BmKynu was detected. We conclude that T102I in BmKYNU causes the red body coloration in the rb strain. Our study proves that B. mori has a unique side branch in the kynurenine pathway, distinctly different from other insects.
Volume 14(2)
Pages 129-40
Published 2009-2-1
DOI 10.1111/j.1365-2443.2008.01257.x
Description rb(赤血)の原因遺伝子はBmKynuである。BmKynuはキヌレニナーゼをコードする。k20 系統(rb/rb)のBmKynuでは、酵素活性を低下させる点突然変異が存在する。
PMID 19170761
MeSH Amino Acid Sequence Animals Base Sequence Bombyx / enzymology Bombyx / genetics* Bombyx / physiology* Cloning, Molecular Color* DNA Mutational Analysis Gene Expression Regulation, Enzymologic Genetic Linkage Hydrolases / genetics* Hydrolases / isolation & purification Hydrolases / metabolism Hydrolases / physiology Models, Biological Molecular Sequence Data Mutation / physiology Phylogeny Polymorphism, Single Nucleotide / physiology Sequence Homology, Amino Acid Skin Pigmentation / genetics*
IF 1.655
Times Cited 25
Silkworms p50 e36 l70 a65 i41 k20