title: Structural features and gene-expression profiles of actin homologs in Porphyra yezoensis (Rhodophyta).
abstract: The marine red alga Porphyra yezoensis contains an actin gene family consisting of at least four isoforms (PyACT1, 2, 3 and 4). The amino acid identity between isoforms exceeds 83%, and each contains a putative nuclear export signal (NES). We scanned the sequences for amino acids in regions homologous to the intermonomeric interface of actin filaments. Few residues expected to engage in cross-linking were conserved between the four isoforms. The results of the sequence analyses suggest that PyACT2 probably functions in the nucleus as a monomer (G-actin) or in other unconventional forms. In addition, the distribution and position of the introns were different from those in florideophycean actin genes. The expression level of PyACT3 in matured gametophytes was significantly higher than in those in a vegetative state, although the mRNA was detected at similar levels in both apical and basal parts of thalli. The expression levels of PyACT2 and 4, on the other hand, did not change significantly between the matured and vegetative gametophytes. The PyACT3 may serve as a molecular marker for monitoring thallus maturation in this species.
authors.affiliation: Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Kitade
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Toshiki
authors.initials: T
authors.lastname: Uji
authors.forename: Satoru
authors.initials: S
authors.lastname: Fukuda
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Endo
authors.forename: Naotsune
authors.initials: N
authors.lastname: Saga
mesh_terms: D000199:Actins / Q000737:chemistry / Q000235:genetics*; D020418:Algal Proteins / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D048028:DNA, Algal / Q000235:genetics; D020869:Gene Expression Profiling; D007438:Introns; D005810:Multigene Family; D044664:Porphyra / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D048030:RNA, Algal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D000199:Actins; D020418:Algal Proteins; D017931:DNA Primers; D048028:DNA, Algal; D020033:Protein Isoforms; D048030:RNA, Algal; D012333:RNA, Messenger