Mutants of Mucor racemosus insensitive to dibutyryl cAMP-mediated changes in cellular morphology

• Published in: Experimental mycology Vol. 6; no. 2; pp. 185 - 189
• Main Authors: Paznokas, John L., Tripp, Matthew L., Wertman, Kenneth F.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1982
• Subjects: fungi; Mucor racemosus; germination; dimorphism; Mucor racemosus; NAD glutamate dehydrogenase; dibutyryl cyclic AMP; mutants
• ISSN: 0147-5975; 1878-4399
• DOI: 10.1016/0147-5975(82)90093-7

Wild-type Mucor racemosus yeasts grown under CO 2 treated with dibutyryl cyclic adenosine 3′,5′-monophosphate (dbcAMP) and glucose do not convert to hyphae during a CO 2-to-air shift. By using procedures which select for hyphal cells, we have isolated a class of mutants of M. racemosus which do convert to hyphae from CO 2 yeast in the presence of dbcAMP and glucose but otherwise respond like wild-type cells to dbcAMP. One of these mutants (MLT-3) has been analyzed and appears to be wild type with respect to two other dbcAMP effects: (1) dbcAMP prevented the appearance of an NAD-dependent glutamate dehydrogenase during a CO 2-to-air shift; (2) dbcAMP inhibited sporangiospore germination. It is probable that the altered gene product in not involved in cAMP metabolism nor does it alter permeability of this organism to dbcAMP, but rather represents an alteration of one of the systems under cAMP control.