THE MATING-TYPE REGION OF SCHIZOSACCHAROMYCES-POMBE CONTAINS AN ESSENTIAL GENE ENCODING A PROTEIN HOMOLOGOUS TO HUMAN MODULATORS OF HIV TRANSACTIVATION

In Schizosaccharomyces pombe, an intrachromosomal crossover between th e mating type (MT) expression locus and one of the silent donor casset tes is lethal due to the loss of the intervening L region. The region contains one essential gene, let1. This gene was cloned and sequenced. The deduced amino acid (aa) sequence of let1 shows extensive homologi es with SUG1 from Saccharomyces cerevisiae. Significant homologies wer e also found with the human HIV transactivation modulators, MSS1 and T BP-1, as well as with subunit 4 of the mammalian 26 S protease. The da ta indicate that let1 is a member of a recently defined multigene fami ly of ATPases.