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Actin of Histriculus cavicola: Characteristics of the Highly Divergent Hypotrich Ciliate Actins 1
Author(s) -
PÉREZROMERO PILAR,
VILLALOBO EDUARDO,
DÍAZRAMOS CORÍN,
CALVO PURIFICACIÓN,
TORRES ANTONIO
Publication year - 1999
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.1999.tb06063.x
Subject(s) - biology , gene , actin , ciliate , coding region , genetics , intron , peptide sequence , nucleic acid sequence , gene isoform , microbiology and biotechnology
A macronuclear gene‐sized molecule carrying an actin gene from the hypotrich ciliate, Histriculus cavicola , was characterized. Southern blot analysis using a coding region probe suggested that actin in H. cavicola is encoded by a single gene. A comparison of the promoter regions indicated that the H. cavicola actin gene has a TATA box in the 5 1 flanking region in a position identical to those in other oxytrich ciliates. The coding sequence of this gene is not interrupted by any introns, and codes for a protein of 375 amino acid residues. This protein shares a high degree of similarity with other oxytrichid actins, and a relatively low similarity with actins from other eukaryotes. Comparative analyses of sequences indicated that most of the amino acid substitutions in hypotrich actins are found in surface loops, while the core structures are well‐conserved. The sites that interact with DNase I and several regions involved in actin‐actin contact have diverged considerably in hypotrich actins, while nucleotide‐binding sites are the best‐conserved interaction motif.