Structural features and gene-expression profiles of actin homologs in Porphyra yezoensis (Rhodophyta).
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.
Kitade
Yukihiro
Y
Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan.
Nakamura
Michiko
M
Uji
Toshiki
T
Fukuda
Satoru
S
Endo
Hirotoshi
H
Saga
Naotsune
N
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
D000199:Actins; D020418:Algal Proteins; D017931:DNA Primers; D048028:DNA, Algal; D020033:Protein Isoforms; D048030:RNA, Algal; D012333:RNA, Messenger