MOLECULAR-CLONING OF A NOVEL SEX-PHEROMONE RESPONSIBLE FOR THE RELEASE OF A DIFFERENT SEX-PHEROMONE IN CLOSTERIUM-PERACEROSUM-STRIGOSUM-LITTORALE COMPLEX

A sex pheromone, protoplast-release-inducing protein (PR-IP) inducer, of the Closterium peracerosum-strigosum-littorale complex is known to induce the release of PR-IF, from mating-type plus (mtf) cells during sexual reproduction. The purified PR-IF inducer was treated with tryps in to obtain internal peptides for determination of partial amino acid sequences. Using these sequences, oligonucleotides were synthesized a nd used as primers for the combined reverse transcription-PCR, A 296 b p cDNA fragment was amplified, permitting the cloning of corresponding full length cDNA (CpPI; Closterium peracerosum-strigosum-littorale co mplex PR-IF inducer). The deduced amino acid sequence of CpPI encodes a protein of 212 amino acid residues of M-r 23,071 whereas portion of the peptide secreted is predicted to have 142 amino acid residues of M -r 15,717 and shows no significant similarity with known proteins. The predicted protein has three possible consensus sequences for asparagi ne-linked glycosylation site. The CpPI gene was expressed when mating- type minus (mt(-)) cells were incubated at a low cell density in the l ight. Nitrogen deprivation from the medium enhances expression of the CpPI gene. An analysis by genomic Southern hybridization revealed that the cDNA probe hybridized to several DNA fragments obtained from both the genome of mt(-) and mt(+) cells. However, in mt- cells, transcrip ts for the PR-IF inducer could not be detected by Northern hybridizati on.