Actin-encoding genes of the hydrozoan Podocoryne carnea.

We have isolated and characterized one genomic clone and five actin-encoding cDNA clones of Podocoryne carnea. The complete nucleotide (nt) sequences of the genomic clone and two cDNA clones were determined. The genomic clone contains two introns at positions also found in actin-encoding genes (Act) of other species. The transcription start point has been mapped, and the promoter sequences CAAT and TATA were identified. The sequenced Act cDNA clones encode identical proteins. The deduced amino acid (aa) sequence differs from the genomic clone in 5 aa residues. All aa substitutions occur in a small region between aa 211 and 303. This variable region has also been sequenced from the remaining Act cDNA clones. From these data, it was concluded that the six Act genes probably code for only two actin proteins (Act). The nt sequences were compared to those of Act from other species. A closer relationship of coelenterate Act to deuterostome than to protostome Act is proposed.