The work that has been done in the last few years had revealed the existence of a hierarchy of regulator genes that control the production of alkaline phosphatase and a family of related enzymes in Neurospora. In the next year, we hope to press forward along several major lines of research that are already in progress: (1) We hope to wind up our proof that the pho-2 region contains the structural gene for alkaline phosphatase, and that a separate, apparently unlinked mutant (tentatively called pho-3) codes for acid phosphatase. (2) We hope to identify the regulatory molecules that are present in isolated nuclei of wide type and mutants of Neurospora by double-labelling and high-resolution electrophoresis. We are concentrating on the product of the nuc-1 gene, and feel that there is a fighting chance for success. (3) We are continuing a genetic study of the nuc-1 and the preg regions in order to find out more about the nature of their products prior to attempts at isolating them.