Characterization of the UDP-glucose pyrophosphorylase gene from the marine red alga Gracilaria gracilis

UDP-glucose pyrophosphorylase (UGPase) is a key enzyme in carbohydrate metabolism, particularly polysaccharide biosynthesis, in red algae. In this report, we characterize at the genomic and cDNA levels the putative UGPase gene of the agarophytic red alga Gracilaria gracilis. The gene is single-copy, devoid of introns, and produces two kinds of transcripts that differ in size by 332 basepairs. The large and small transcripts appear to utilize distinct polyadenylation signals. The putative protein has 495 amino acids, and is about 50% identical in sequence to its homplogs in plants, animals and fungi. Sequencing of the,genomic clone revealed that another gene, potentially encoding a DNA helicase and containing a 76 bp-intron near its 3' end, occurs 376 bp downstream of the UGPase gene.