Shani, M., Department of Cell Biology, Heidelberg, Germany
Nudel, U., Department of Cell Biology, Heidelberg, Germany
Zevin-Sonkin, D., Department of Cell Biology, Heidelberg, Germany
Zakut, R., Department of Cell Biology, Heidelberg, Germany, Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel
Givol, D., Department of Cell Biology, Heidelberg, Germany, Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel
Katcoff, D., Department of Cell Biology, Heidelberg, Germany
Carmon, Y., Department of Cell Biology, Heidelberg, Germany
Reiter, J., Department of Cell Biology, Heidelberg, Germany, European Molecular Biology Laboratory, Heidelberg, Germany
Frischauf, A.M., Department of Cell Biology, Heidelberg, Germany, European Molecular Biology Laboratory, Heidelberg, Germany
Yaffe, D., Department of Cell Biology, Heidelberg, Germany

Plasmids p749, p106, and p150 contain cDNA inserts complementary to rat skeletal muscle actin mRNA. Nucleotide sequence analysis indicates the following sequence relationships: p749 specifies codons 171 to 360; p150 specifies codons 357 to 374 together with 120 nucleotides of the 3'-non-translated region; p106 specifies the last actin amino acid codon, the termination codon and the entire 3' non-translated region. Plasmid p749 hybridized with RNA extracted from rat skeletal muscle, cardiac muscle, smooth (stomach) muscle, and from brain. It also hybridizes well with RNA extracted from skeletal muscle and brain of dog and chick. Plasmid p106 hybridized specifically with rat striated muscles (skeletal and cardiac muscle) mRNA but not with mRNA from rat stomach and from rat brain. It also hybridized to RNA extracted from skeletal muscle of rabbit and dog but not from chick. Thermal stability of the hybrids and sensitivity to S1 digestion also indicated substantial divergence between the 3' untranslated end of rat and dog skeletal muscle actins. The investigation shows that the coding regions of actin genes are highly conserved, whereas the 3' non-coding regions diverged considerably during evolution. Probes constructed from the 3' non-coding regions of actin mRNAs can be used to identify the various actin mRNA and actin genes. © 1981 IRL Press Limited.