Normal silkworms (Bombyx mori) have opaque larval skin due to uric acid accumulation in the epidermis while a mutant, og, is translucent owing to a deficiency in xanthine dehydrogenase (XDH), which synthesizes uric acid. Molybdenum cofactor (MoCo) sulfurase is responsible for XDH activation in various organisms. A silkworm MoCo sulfurase gene was cloned and found to be on the og locus, whose mutant alleles, ogk and ogt, show premature stop codons, proving that og is the MoCo sulfurase gene. It was observed that a miniature inverted-repeat transposable element (MITE), named Organdy, when inserted in an ogt mutant allele exon, causes unstable splicing of a downstream intron leading to incomplete open reading frames.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Insect Science