A defect in purine nucleotide metabolism in the silkworm, Bombyx mori, causes a translucent larval integument and male infertility
A defect in purine nucleotide metabolism in the silkworm, Bombyx mori, causes a translucent larval integument and male infertility
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DOI：
10.1016/j.ibmb.2020.103458
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发表时间：
2020-11-01
影响因子：
3.8
通讯作者：
Banno, Yutaka
中科院分区：
文献类型：
--
作者：
Fujii, Tsuguru;Kakino, Kohei;Banno, Yutaka
P-油质(OP)是家蚕的一个新突变体，具有半透明的幼体被和雄性不育。阐明op突变体的致病基因将有助于了解幼虫珠被着色和雄性可育性的遗传机制。利用家蚕和柑橘之间的多态性，OP基因座被缩小到一个375kb的区域。通过RNA-seq分析，我们发现OP突变体在位于375-kb区域的KWMTBOMO13770基因上存在移码突变。数据库搜索表明，该基因是家蚕细胞质5‘-核苷酸酶II基因(CN-II)的同源基因，它介导了肌苷单磷酸(IMP)向尿酸前体肌苷的转化。CRISPR/Cas9介导的BM-CN-II基因敲除突变体具有半透明的被被，并且在基因敲除蛾与+/OP蛾的杂交中出现半透明的幼虫。此外，口服肌苷可挽救因BM-CN-II基因突变而导致的半透明表型和幼虫被片中尿酸含量的降低。这些结果表明，BM-CN-II基因与OP表型有关，BM-CN-II基因的分子功能是将IMP转化为肌苷。我们还讨论了BmcN-II基因与男性生育能力的遗传关系。
p-oily (op) is a novel mutant of Bombyx mori exhibiting translucent larval integument and male infertility. Elucidation of the causative gene of the op mutant will help understand the genetic mechanism underlying larval integument coloration and male fertility. Using polymorphisms between B. mori and B. mandarin, the op locus was narrowed down to a 375-kb region. Using RNA-seq analysis, we found that op mutants have a frameshift mutation in the KWMTBOMO13770 gene located in the 375-kb region. A database search indicated that this gene is the human cytosolic 5'-nucleotidase II gene (cN-II) homolog in Bombyx, which mediates the conversion of inosine monophosphate (IMP) to inosine, a precursor of uric acid. CRISPR/Cas9-mediated knockout mutants of the Bm-cN-II gene showed translucent integuments, and there appeared translucent larvae in the crosses between knockout moths and +/op moths. Moreover, the translucent phenotype of, and decreased uric acid content in the larval integument caused by the mutations in the Bm-cN-II gene were rescued by oral administration of inosine. These results indicated that the Bm-cN-II gene is responsible for the op phenotype and that the molecular function of the Bm-cN-II gene is the conversion of IMP to inosine. We also discuss the genetic relationship between the BmcN-II gene and male fertility.