ThensdDgene encodes a putative GATA‐type transcription factor necessary for sexual development ofAspergillus nidulans

Abstract

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 (Hülle 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).

More Than a Repair Enzyme:Aspergillus nidulansPhotolyase-like CryA Is a Regulator of Sexual Development

“…The cryptochrome functions of the CryA protein, namely, regulation of gene expression and a blue-light reception, are corroborated by several findings: the fungal cryA⌬ mutant strain develops sexual organs-Hü lle cells-in submerged culture conditions, which usually repress sexual and asexual differentiation of in A. nidulans by maintaining vegetative growth. This phenotype has also been described for a mutant strain of rosA, as well as for strains overexpressing sexual regulators nsdD and veA (Han et al, 2001;Kim et al, 2002;Vienken et al, 2005). A common feature of these genes is that they encode transcriptional regulatory proteins for sexual development.…”

“…A common feature of these genes is that they encode transcriptional regulatory proteins for sexual development. VeA is a light-dependent regulator of sexual development without any obvious DNA binding domain (Kim et al, 2002), NsdD is a putative GATA type transcription factor necessary for sexual development (Han et al, 2001), and RosA is a Zn(II) 2 Cys 6 transcription factor required for the repression of sexual development . Our detailed analysis of the transcription data revealed a hierarchical feedback loop between activator and repressor elements.…”

“…The formation of Hü lle cells in the cryA mutant under inappropriate conditions is reminiscent of an imbalance of fungal developmental regulators. When overexpressed, the light-dependent sexual regulator veA or sexual transcription factor nsdD cause Hü lle cell formation in submerged culture (Han et al, 2001;Kim et al, 2002). The veA gene is responsible for light-dependent fruit body formation in A. nidulans (Mooney and Yager, 1990;Kim et al, 2002), and never in sexual development (NsdD) is a putative GATA-type transcription factor that activates sexual development (Han et al, 2001).…”

Spotlight on Aspergillus nidulans photosensory systems

“…1A). During the last decade a couple of genes including nsdD, nosA, veA, rcoA necessary for cleistothecia formation have been studied (Han et al, 2001;Kim et al, 2002;Todd et al, 2006;Vienken and Fischer, 2006).…”

ThensdCGene Encoding a Putative C2H2-Type Transcription Factor Is a Key Activator of Sexual Development inAspergillus nidulans

“…A number of genes involved in these stages have been identified, although detailed knowledge of their functions at each stage is incomplete. They include signaling components such as the G-protein-coupled receptor system, mitogen-activated protein kinase cascades, and 1 cAMP pathways (Han and Prade 2002;Kawasaki et al 2002;Wei et al 2003;Han et al 2004;Seo et al 2004) and also several putative transcription factors including StuA, SteA, NsdD, and RosA (Miller et al 1992;Pascon and Miller 2000;Han et al 2001;Vienken et al 2005).…”