Complete nucleotide sequence of a sea urchin actin gene

Abstract

He have determined the complete nucleotide sequence of a sea urchin actin gene, including the entire protein-coding sequence, introns and approximately 500 and 700 nucleotides adjacent to protein-coding-sequence on the 5′ and 3′ sides, respectively. This gene is split between codons 121 and 122 and within codon 204 by two introns which are 233 and 181 nucleotides in length, respectively. Comparison of the sequence of the two introns indicates a region of distant relatedness which covers about 25% of their lengths, suggesting that these sequences might have derived from a common ancestral sequence. The encoded amino acid sequence, which matches closely with that reported for actins from other species, is more cytoplasmic-like than muscle-like when compared to vertebrate actins. Analysis of the coding-flanking regions indicates the presence of sequences similar to those thought to be important for initiation of transcription and poly-adenylation of mRNA. The location of these sequences and the size of an actin mRNA, transcribed from this or a very closely related gene, suggests that initiation occurs 347 nucleotides 51 of coding and polyadenylation approximately 515 nucleotides 3′ of coding.