The nsdD gene encodes a putative GATA-type transcription factor necessary for sexual development of Aspergillus nidulans
The nsdD gene encodes a putative GATA-type transcription factor necessary for sexual development of Aspergillus nidulans
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DOI：
10.1046/j.1365-2958.2001.02472.x
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发表时间：
2001-07-01
影响因子：
3.6
通讯作者：
Han, DM
中科院分区：
文献类型：
--
作者：
Han, KH;Han, KY;Han, DM
有性生殖和无性生殖的能力是同宗配合的子囊菌构巢曲霉的特征之一。与其他曲霉属物种不同，构巢曲霉的有性发育似乎受内部和外部刺激的调控。为了开始了解构巢曲霉的有性生殖，我们先前分离并鉴定了几种NSD（永不进行有性发育）突变体，这些突变体无法产生任何有性生殖器官，并确定了四个互补群，即nsdA、nsdB、nsdC和nsdD。nsdD基因已被分离出来，预计它编码一种具有IVb型锌指DNA结合结构域的GATA型转录因子。nsdD基因的mRNA在营养生长的早期阶段开始积累，并且随着有性发育的进行其水平升高。然而，在无性孢子形成过程中它会减少，并且在分生孢子中未检测到nsdD mRNA。nsdD的缺失导致即使在优先促进有性发育的条件下也没有闭囊壳（子实体）形成，这表明nsdD对有性发育是必需的。相反，当nsdD基因过表达时，即使在通常完全阻断有性发育的液体培养中也会形成有性特异性器官（厚壁细胞），并且在固体培养基上闭囊壳的数量也显著增加。这些结果使我们提出nsdD基因在激活构巢曲霉的有性发育中起作用。nsdD基因的多个拷贝可以抑制nsdB5和veA1，这表明nsdD要么在这些基因的下游起作用，要么可能在重叠的途径中起作用。
The ability to reproduce both sexually and asexually is one of the characteristics of the homothalic ascomycete Aspergillus nidulans. Unlike the other Aspergillus species, A. nidulans undergoes sexual development that seems to be regulated by internal and external stimuli. To begin to understand the sexual reproduction of A. nidulans we previously isolated and characterized several NSD (never in sexual development) mutants that failed to produce any sexual reproductive organs, and identified four complementation groups, nsdA, nsdB, nsdC, and nsdD. The nsdD gene has been isolated, and it is predicted to encode a GATA-type transcription factor with the type IVb zinc finger DNA-binding domain. The mRNA of the nsdD gene started to accumulate in the early phase of vegetative growth, and the level increased as sexual development proceeded. However, it decreased during asexual sporulation and no nsdD mRNA was detected in conidia. Deletion of nsdD resulted in no cleistothecia (fruiting bodies) formation, even under the conditions that preferentially promoted sexual development, indicating that nsdD is necessary for sexual development. In contrast, when the nsdD gene was over-expressed, sexual-specific organ (Hulle cell) was formed even in submerged culture, which normally completely blocked sexual development, and the number of cleistothecia was also dramatically increased on solid medium. These results lead us to propose that the nsdD gene functions in activating sexual development of A. nidulans. Multiple copies of the nsdD gene could suppress nsdB5 and veA1, indicating that either nsdD acts downstream of these genes or possibly functions in overlapping pathway(s).