Gene structure and domain architecture in the biomineralizing protein Lustrin A from the abalone Haliotis rufescens

Abstract

Among the proteins that play a role in molluscan biomineralization, Lustrin A was the first to be investigated and it remains the most-well studied. It is composed of many repetitive domains, which appear to be present in all members of the family Haliotidae. For the first time we have sequenced the complete gene (34,093 bp), coding for the cDNA of Haliotis rufescens Lustrin A, using long PCRs and cloning. It encompasses 34 exons and 33 introns, including 10 minisatellite-rich regions present in eight of these introns. The corresponding glycine and serine-rich (GS) domain and the C-terminus-WAP domain are well delimited by phase 1 introns, while phase 0 introns separate the Cysteine-rich domains. Within these domains, the Hr_Lustrin gene contains 10 phase 1 introns. No codon bias was detected in the nucleotide composition. We discuss the observe intron specificity together with the absence of exons corresponding to putative spacer regions or basic domains. We also compared H. rufescens Lustrin A with the H. tuberculata Lustrin A gene partial sequence.