Molecular cloning and characterization of a fructose-1,6-biphosphate aldolase cDNA from the deep-sea scallop Placopecten magellanicus

摘要

The deep-sea scallop Placopecten magellanicus is an important member of commercial fisheries along the coast of Northeastern United States and Atlantic Canada. A cDNA encoding a glycolytic pathway enzyme fructose-1,6-biphosphate aldolase, was isolated from a sea scallop adductor muscle-specific cDNA library and sequenced from both directions. The full-length cDNA is a 1627 base-pair (bp) long sequence that has a 62 bp 5' untranslated region, a 1092 bp open-reading frame, and a 473 bp 3' untranslated region including a 24 bp polyA tail. The open-reading frame encodes a 39.3 kDa protein with 363 amino acids. The protein has 183 nonpolar, 94 polar uncharged, and 86 polar-charged amino acids. Several amino acids show bias for codons with G/C at their third position. The cDNA has 28 unique restriction sites, including common restriction enzymes such as SacI, BamHI, TaqI, and BstEII. The aldolase is a highly conserved protein with 66% sequence identity with that of Schistosoma mansoni, 65% with that of Drosophila melanogaster, 62% with that of Homo sapiens, and 57% with that of Oryza sativa. Southern blot analysis indicates that aldolase in sea scallops belongs to a family with 4 to 10 putative genes. Northern blot analysis shows that this gene is expressed only in adductor muscles. Hybridization of an aldolase cDNA probe to genomic DNA from several individuals revealed restriction fragment length polymorphisms at several loci, indicating potential use of this cDNA as a marker in genetic studies of sea scallops.