Expression of a constitutively active Ca2+/calmodulin-dependent kinase in Aspergillus nidulans spores prevents germination and entry into the cell cycle
Expression of a constitutively active Ca2+/calmodulin-dependent kinase in Aspergillus nidulans spores prevents germination and entry into the cell cycle
复制标题
DOI：
10.1074/jbc.272.6.3223
复制
发表时间：
1997-02-07
影响因子：
4.8
通讯作者：
Means, AR
中科院分区：
文献类型：
--
作者：
Dayton, JS;Sumi, M;Means, AR
Ca 2 +/钙调素依赖性蛋白激酶（CaMK）的独特基因已被证明在构巢曲霉中是必需的。基因的破坏阻止孢子进入核分裂周期。在这里，我们表明，表达的组成型活性形式的钙调蛋白激酶也防止孢子进入第一个S期发芽刺激。组成型活性激酶的表达诱导G（0）/G（1）中NIME（细胞周期蛋白B）/NIMX（cdc 2）的过早激活。由于NIMX（cdc 2）存在于孢子中，成熟促进因子活性的提高可能继发于NIME（细胞周期蛋白B）的早期产生或成熟促进因子的翻译后修饰。组成型活性CaMK的表达也导致NIMA激酶活性在萌发信号的1小时内出现。这些结果支持了成熟促进因子和NIMA活性在A.表明这些活性中的一种或两种的不定期出现可能足以阻止构巢曲霉孢子进入DNA合成。
The unique gene for Ca2+/calmodulin-dependent protein kinase (CaMK) has been shown to be essential in Aspergillus nidulans. Disruption of the gene prevents entry of spores into the nuclear division cycle. Here we show that expression of a constitutively active form of CaMK also prevents spores from entering the first S phase in response to a germinating stimulus. Expression of the constitutively active kinase induces premature activation of NIME(cyclin B)/NIMX(cdc2) in G(0)/G(1). As NIMX(cdc2) is present in spores, the elevation of maturation promotion factor activity may be secondary to the early production of NIME(cyclin B) or post-translation modification of maturation promotion factor. The expression of the constitutively active CaMK also results in the appearance of NIMA kinase activity within 1 h of the germinating signal. These results support the contention that the activities of maturation promotion factor and NIMA are coincidentally regulated in A. nidulans and suggest that the unscheduled appearance of one or both of these activities may be sufficient to prevent A, nidulans spores from entering into DNA synthesis.