Gold S, Duncan G, Barrett K, Kronstad J
Department of Microbiology, University of British Columbia, Vancouver, Canada.
Genes Dev. 1994 Dec 1;8(23):2805-16. doi: 10.1101/gad.8.23.2805.
The fungal pathogen Ustilago maydis exhibits a dimorphic switch from budding to filamentous growth in response to mating interactions and environmental conditions. We have found that disruption of the uac1 gene, encoding adenylate cyclase, results in a constitutively filamentous phenotype. Budding is restored to the uac1 mutant upon growth in the presence of cAMP or by extragenic suppression because of a mutation in the ubc1 gene. The ubc1 gene encodes a type II regulatory subunit of cAMP-dependent protein kinase (PKA); defects in this gene attenuate the filamentous growth that normally occurs in response to mating and exposure to air. Growth of wild-type cells in cAMP and mutation of the ubc1 gene also cause defects in the separation of mother and daughter cells (cytokinesis) and alter bud site selection. These results indicate a key role for cAMP and PKA in morphogenesis in U. maydis; this role may be common among dimorphic fungal pathogens.
真菌病原体玉米黑粉菌（Ustilago maydis）会根据交配相互作用和环境条件，从出芽生长转变为丝状生长，呈现出二态性转变。我们发现，编码腺苷酸环化酶的uac1基因被破坏会导致一种组成型丝状表型。在存在cAMP的情况下生长或由于ubc1基因发生突变导致的基因外抑制，可使uac1突变体恢复出芽生长。ubc1基因编码cAMP依赖性蛋白激酶（PKA）的II型调节亚基；该基因的缺陷会减弱通常因交配和暴露于空气中而发生的丝状生长。野生型细胞在cAMP中生长以及ubc1基因突变也会导致母细胞和子细胞分离（胞质分裂）出现缺陷，并改变芽位点选择。这些结果表明cAMP和PKA在玉米黑粉菌的形态发生中起关键作用；这种作用可能在二态性真菌病原体中很常见。
