veA-dependent expressions of indB and indD encoding proteins that interact with NSDD, a GATA-type transcription factor required for sexual development inAspergillus nidulans.

Nak-Jung Kwon, Dong-Min Han1, Suhn-Kee Chae.

Abstract: 

In nsdD mutants of Aspergillus nidulans, no sexual organs including cleistothecia, Hull cells, and primodia were ever found. Molecular cloning of the nsdDgene revealed that nsdD encoded a putative GATA type transcription factor carrying a type IVb zinc finger motif at the C-terminal end. To clarify the NSDD function, proteins interacting with NSDD have been screened using the yeast two-hybrid system. Two IND (Interactor of NSDD) proteins, INDB and INDD were isolated and characterized further. Determination of indB and indD cDNA sequences revealed open reading frames of 648 bp and 642 bp, encoding polypeptides of 215 and 213 amino acids, respectively. INDB and INDD showed 42% amino acid sequence identity and also shared similarities to an ORF in Neurospora crassa. NSDD-INDB and NSDD-INDD interactions were confirmed in vitro using a GST-pull down assay. Both proteins interacted with the Zn-finger domain of NSDD. The N-terminus of INDB and the C-terminus of INDD were responsible for the NSDD interaction. INDB and INDD was able to interact each other. Self association of INDB but not for INDD was observed, too. In Northern analysis, 1.2 kb transcripts were detected for both genes. The indB transcripts expressed to similar levels during asexual development, but increased at 20-30 hour after induction of sexual development, then decreased. In contrast, the indD transcript was the most abundant at the initial asexual developmental stage. Furthermore, both kinds of transcripts were highly produced in veAmutant strains, but repressed in veA+ wild type background, indicatingveA-dependent expressions. veA mutations conferred defectiveness in sexual differentiation. Our results suggest that increased expressions of INDB and INDD in veAbackground might affect NSDD function negatively by binding to the Zn-finger region of NSDD to block DNA binding. [Supported by grants from KOSEF]
2003

abstract No: 

Fungal Genet. Newsl. 50 (Supl):abstract

Full conference title: 

22nd Fungal Genetics Conference
    • Fungal Genetics Conference 22nd (2001)