Eh. Pardo et al., MULTIPLE VERSIONS OF THE A MATING-TYPE LOCUS OF COPRINUS-CINEREUS AREGENERATED BY 3 PARALOGOUS PAIRS OF MULTIALLELIC HOMEOBOX GENES, Genetics, 144(1), 1996, pp. 87-94
The A mating type locus of Coprinus cinereus determines mating compati
bility by regulating essential steps in sexual development. Each A loc
us contains several genes separated into two functionally independent
complexes termed A alpha and A beta, and the multiple alleles of these
genes generate an estimated 160 A mating specificities. The genes enc
ode two classes of homeodomain-containing proteins designated HD1 and
HD2. In this report we describe two newly cloned loci, A2 and A5, and
compare them with A42, A43 and A6 that we have described previously. A
n A beta-null locus, retaining just a single active HD1 gene from the
ct-complex, was generated by mutation. Using this as a transformation
host, gene combinations that promote A-regulated development were iden
tified. We demonstrate that each A locus contains members of three par
alogous pairs of HD1 and HD2 genes. Different allelic versions of gene
pairs are compatible but paralogous genes are incompatible. The genes
present in four uncloned A loci were deduced using Southern analyses
and transformations with available cloned genes. The combined analysis
of nine A factors identifies sufficient A gene alleles to generate at
least 72 A mating specificities.