Cloning and genomic sequence of the Physarum polycephalum Ppras1 gene, a homologue of the ras protooncogene.
We have cloned the genomic copy of the Ppras1 gene, a homologue of the ras proto-oncogene, from the true slime mold Physarum polycephalum. Ppras1 contains five small introns, four of which have a high content of pyrimidines. The (dC)-homopolymers present in introns 4 and 5 may be responsible for the observed recA-independent deletion in Ppras1 upon amplification of the Ppras1-bearing plasmid by choramphenicol. Although Ppras1 exhibits amino acid and nucleotide homologies with the DdrasG gene, a homologue of ras from another slime mold, Distyostelium discoideum, locations and sequences of their introns are quite different. This discordance suggests that introns of the ras genes in these species were acquired independently.
Trzcinska-Danielewicz
J
J
Institute of Biochemistry, Warsaw University, Poland.
Kozlowski
P
P
Toczko
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005800:Genes, Fungal; D011905:Genes, ras; D008969:Molecular Sequence Data; D016839:Physarum polycephalum / Q000235:genetics*