Ziv Carmit, Gorovits Rena, Yarden Oded
Department of Plant Pathology and Microbiology, The Otto Warburg Minerva Center for Agricultural Biotechnology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Fungal Genet Biol. 2008 Feb;45(2):103-16. doi: 10.1016/j.fgb.2007.05.005. Epub 2007 Jun 10.
A defect in mcb, encoding the cAMP-dependent protein kinase A (PKA) regulatory subunit in Neurospora crassa, which confers an apolar growth phenotype, is accompanied by an increase in PKA activity levels. Both PKA and CRE-1 [a key carbon catabolite repression (CCR) regulator] mediate the cellular response to carbon-source availability. Inactivation of the cre-1 gene resulted in reduced growth rate, abnormal hyphal morphology and altered CCR. Both PKA and CRE-1 affected morphology in a carbon-dependent manner, as fructose suppressed the apolar morphology of the mcb strain and enabled faster growth of the Deltacre-1 mutant. An increase in cre-1 transcript abundance was observed in mcb and a reduction in PKA activity levels was measured in Deltacre-1. CRE-1 is involved in determining PKA-dependent polarity, as an mcb;Deltacre-1 strain displayed partial reestablishment of hyphal polarity. Taken together, our results demonstrate regulatory interactions between PKA and CRE-1 that affect cell polarity in a filamentous fungus.
粗糙脉孢菌中编码环磷酸腺苷（cAMP）依赖性蛋白激酶A（PKA）调节亚基的mcb存在缺陷，会导致非极性生长表型，同时PKA活性水平会升高。PKA和CRE-1（一种关键的碳分解代谢物阻遏（CCR）调节因子）都介导细胞对碳源可用性的反应。cre-1基因的失活导致生长速率降低、菌丝形态异常和CCR改变。PKA和CRE-1都以碳依赖的方式影响形态，因为果糖抑制了mcb菌株的非极性形态，并使Δcre-1突变体生长得更快。在mcb中观察到cre-1转录本丰度增加，在Δcre-1中检测到PKA活性水平降低。CRE-1参与确定PKA依赖性极性，因为mcb;Δcre-1菌株显示出菌丝极性的部分重建。综上所述，我们的结果证明了PKA和CRE-1之间的调节相互作用，这种相互作用影响丝状真菌中的细胞极性。
