A putative rhamnogalacturonase required for sexual development of Neurospora crassa.
A putative rhamnogalacturonase required for sexual development of Neurospora crassa.
复制标题
粗糙脉孢菌性发育所需的假定鼠李糖半乳糖醛酸酶。
DOI：
10.1093/genetics/146.2.531
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发表时间：
1997
期刊：
影响因子：
3.3
通讯作者：
Metzenberg,RL
中科院分区：
文献类型：
--
作者：
Nelson,MA;Merino,ST;Metzenberg,RL
在以前的工作中，丝状真菌粗糙脉孢菌的asd-1（子囊发育）基因被鉴定为在性周期中优先表达的基因，并被证明是正常性发育所必需的。已对该asd-1基因进行了测序和进一步鉴定。它包含两个内含子，其中第一个是在框架内和低效或差异剪接。预测的ASD-1蛋白与棘孢曲霉的鼠李糖半乳糖醛酸酶B具有广泛的同源性，该酶切割果胶的分支毛状区域内的主链。在同源异源asd-1杂交中，有性发育开始并形成大量正常大小的子囊。然而，不发生子囊孢子划分，也不产生有性后代。由于mostasd-1asci含有8个细胞核，两次减数分裂和随后的有丝分裂的典型的正常杂交似乎发生，但单倍体细胞核不分配到子囊孢子。在野生型杂交中，ASD-1蛋白大量存在于crozier和年轻的子囊中，但在含有发育中的子囊孢子的更成熟的子囊中只能微弱地检测到。模型来解释性发育中的鼠李糖半乳糖醛酸酶的可能作用。
In previous work, theasd-1(ascusdevelopment) gene of the filamentous fungusNeurospora crassawas identified as a gene expressed preferentially during the sexual cycle and shown to be essential for normal sexual development. Theasd-1gene has been sequenced and further characterized. It contains two introns, the first of which is in-frame and inefficiently or differentially spliced. The predicted ASD-1 protein has extensive homology with rhamnogalacturonase B ofAspergillus aculeatus, which cleaves the backbone within the ramified hairy regions of pectin. In homozygousasd-1crosses, sexual development is initiated and large numbers of normal-sized asci are formed. Ascospore delineation does not occur, however, and no sexual progeny are produced. As mostasd-1asci contain eight nuclei, the two meiotic divisions and subsequent mitotic division typical of normal crosses seem to occur, but the haploid nuclei are not partitioned into ascospores. In wild-type crosses, the ASD-1 protein is present in large amounts in croziers and young asci, but it is only faintly detectable in more mature asci containing developing ascospores. Models to explain the possible role of a rhamnogalacturonase in sexual development are presented.