Scooter, a new active transposon in Schizophyllum commune, has disrupted two genes regulating signal transduction

Two copies of scooter, a DNA-mediated transposon in the basidiomycetous fun gus Schizophyllum commune, were characterized. Scooter is the first transpo son isolated from S. commune. Scooter creates 8-bp target site duplications , comparable to members of the hAT superfamily, and has 32-bp terminal inve rted repeats. Both copies of scooter are nonautonomous elements capable of movement. Southern blot hybridizations show that scooter-related sequences are present in all S. commune strains tested. Scooter-1 was identified init ially as an insertion in the B beta2 pheromone receptor gene, bbr2, leading to a partial defect in mating. Scooter-2 spontaneously disrupted a gene to produce the frequently occurring morphological mutant phenotype known as t hin. The scooter-2 insert permitted cloning of the disrupted gene, thn1, wh ich encodes a putative regulator of G protein signaling (RGS) protein. Spon taneous insertion of scooter into genes with identifiable mutant phenotypes constitutes the first evidence of active transposition of a DNA-mediated t ransposon in a basidiomycete.