Cloning and expression of genes from the genomic region between genes cd and 30 of bacteriophage T4.

Ten open reading frames (ORFs) from the cd-30 region of bacteriophage T4, as well as genes 31 and rIII, have been cloned, and all were found to be expressed in a T7 RNA polymerase system. Expression data confirm the existence of genes 31.2, 31.1, 31, rIII, 30.9, 30.8, 30.7, 30.6, 30.5, 30.4, 30.3 and 30.2, which predict peptides of 78, 102, 111, 82, 58, 110, 121, 95, 65, 68, 152 and 278 amino acids (aa), respectively. The major product of gene 30.9 is a basic peptide initiated at the second AUG codon that is found 42 nucleotides downstream and in frame from the first AUG. A plasmid carrying gene 30.3 expresses two different peptides, one of which is of the size predicted for gp30.3. By site-directed mutagenesis we have shown that the smaller peptide is encoded by gene 30.3' which is completely embedded within gene 30.3, but in a different reading frame. Gene 30.3' encodes a 75-aa basic peptide with its C terminus rich in charged aa.