title: Characterization of the polyubiquitin gene in the marine red alga Gracilaria verrucosa.
abstract: We have cloned a nuclear gene (UBI6R) and corresponding cDNAs that encode polyubiquitin in the florideophycidean red alga Gracilaria verrucosa. The gene encodes a polyubiquitin composed of six tandem ubiquitin units, followed by a single glutamine residue. The deduced amino acid sequences are identical among all six units, and identical to the ubiquitin of the florideophyte Aglaothamnion neglectum. There is high sequence similarity among the red algal ubiquitins and those of animals, green plants, fungi and several protists. Only one polyubiquitin gene was found by Southern hybridization analysis of G. verrucosa nuclear DNA. The upstream region of the gene is rich in putative cis-acting transcription-regulatory elements, including a putative heat-responsive element. Poly(A) addition to UBI6R mRNA was observed in cDNAs at four different sites, implicating the sequences AATAAA and (or) AGTAAA as poly(A) addition signals. The polyubiquitin genes of red algae show features of concerted evolution, but appear to be subject to less sequence homogenization than those of animals.
authors.affiliation: Institute for Marine Biosciences, National Research Council of Canada, Halifax, Nova Scotia.
authors.forename: Y H
authors.initials: YH
authors.lastname: Zhou
authors.forename: M A
authors.initials: MA
authors.lastname: Ragan
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001704:Biopolymers / Q000235:genetics*; D003001:Cloning, Molecular; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D025821:Polyubiquitin; D000461:Rhodophyta / Q000235:genetics*; D016415:Sequence Alignment; D014452:Ubiquitins / Q000235:genetics*
chemical_list: D001704:Biopolymers; D014452:Ubiquitins; D025821:Polyubiquitin