title: Expressed 2-5A synthetase genes and pseudogenes in the marine sponge Geodia barretti.
abstract: The 2',5'-oligoadenylate synthetases (2-5A synthetases, OAS) form a family of proteins presented in many branches of Metazoa. The phylum Porifera (sponges) contains OAS proteins which are different from those in vertebrates and form a distinct OAS subfamily. In turn, OAS proteins from different genera of Demospongia show rather low similarities in their primary structures. To ascertain divergence of the OAS genes within a particular sponge genus, we identified the OAS genes from the marine sponge Geodia barretti and compared them with those from another member of the genus Geodia, Geodia cydonium. The identity and similarity of the OAS sequences found in G. barretti with those from G. cydonium were considerably higher than identities and similarities compared with those from other sponges, 75% and 85% versus 27-30% and 42-47%, respectively. We also established the presence of a transcriptionally active polymorphic OAS pseudogene in the genome of G. barretti. The transcripts of the OAS pseudogene(s) lack several internal exons encoding necessary motifs for OAS enzymatic activity. The maintenance and further diversification of OAS gene(s) and pseudogene(s) suggest the prevalence of gene duplication events over the loss of gene duplicates in Geodia genomes during the evolution.
authors.affiliation: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
authors.forename: Kerli
authors.initials: K
authors.lastname: Vallmann
authors.forename: Nele
authors.initials: N
authors.lastname: Aas
authors.forename: Tõnu
authors.initials: T
authors.lastname: Reintamm
authors.forename: Annika
authors.initials: A
authors.lastname: Lopp
authors.forename: Anne
authors.initials: A
authors.lastname: Kuusksalu
authors.forename: Merike
authors.initials: M
authors.lastname: Kelve
mesh_terms: D015088:2',5'-Oligoadenylate Synthetase / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons; D016678:Genome; D047231:Geodia / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011544:Pseudogenes; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D015088:2',5'-Oligoadenylate Synthetase