title: Mutation of a vitelline membrane protein, BmEP80, is responsible for the silkworm "Ming" lethal egg mutant.
abstract: The egg stage is an important stage in the silkworm (Bombyx mori) life cycle. Normal silkworm eggs are usually short, elliptical, and laterally flattened, with a sometimes hollowed surface on the lateral side. However, the eggs laid by homozygous recessive "Ming" lethal egg mutants (l-e(m)) lose water and become concaved around 1h, ultimately exhibiting a triangular shape on the egg surfaces. We performed positional cloning, and narrowed down the region containing the gene responsible for the l-e(m) mutant to 360 kb on chromosome 10 using 2287 F(2) individuals. Using expression analysis and RNA interference, the best l-e(m) candidate gene was shown to be BmEP80. The results of the inverse polymerase chain reaction showed that an ~1.9 kb region from the 3' untranslated region of BmVMP23 to the forepart of BmEP80 was replaced by a >100 kb DNA fragment in the l-e(m) mutant. Several eggs laid by the normal moths injected with BmEP80 small interfering RNAs were evidently depressed and exhibited a triangular shape on the surface. The phenotype exhibited was consistent with the eggs laid by the l-e(m) mutant. Moreover, two-dimensional gel electrophoresis showed that the BmEP80 protein was expressed in the ovary from the 9th day of the pupa stage to eclosion in the wild-type silkworm, but was absent in the l-e(m) mutant. These results indicate that BmEP80 is responsible for the l-e(m) mutation.
authors.affiliation: The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China.
authors.forename: Anli
authors.initials: A
authors.lastname: Chen
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Zhao
authors.forename: Shunming
authors.initials: S
authors.lastname: Tang
authors.forename: Xingjia
authors.initials: X
authors.lastname: Shen
authors.forename: Guozheng
authors.initials: G
authors.lastname: Zhang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Qiu
authors.forename: Dingguo
authors.initials: D
authors.lastname: Xia
authors.forename: Yongping
authors.initials: Y
authors.lastname: Huang
authors.forename: Yunmin
authors.initials: Y
authors.lastname: Xu
authors.forename: Ningjia
authors.initials: N
authors.lastname: He
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics*; D002874:Chromosome Mapping; D004252:DNA Mutational Analysis; D004527:Egg Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D005804:Genes, Lethal; D056726:Genetic Association Studies; D008040:Genetic Linkage; D054643:INDEL Mutation; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D014817:Vitelline Membrane / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D004527:Egg Proteins; D019476:Insect Proteins; C035651:vitelline membrane proteins