Our overall objective has been to understand the molecular details of gene expression. We are studying transcription and translation, and in each case we are taking advantange of the genetic potential built into the host-virus system of E. coli-T4. BIBLIOGRAPHIC REFERENCES: Singer, B.S. and L. Gold. 1976. A mutation that confers temperature sensitivity on the translation of rIIB in Bacteriophage T4. J. Mol. Biol. 103:627-646. Snyder, L., L. Gold, and E. Kutter. 1976. Production of viable T4 coliphage whose DNA has mostly cytosine. PNAS 73: 3098-3102 (No reprints available at this time).