The role, interaction and regulation of the velvet regulator VelB in Aspergillus nidulans

PLoS One. 2012;7(9):e45935. doi: 10.1371/journal.pone.0045935. Epub 2012 Sep 25.

Abstract

The multifunctional regulator VelB physically interacts with other velvet regulators and the resulting complexes govern development and secondary metabolism in the filamentous fungus Aspergillus nidulans. Here, we further characterize VelB's role in governing asexual development and conidiogenesis in A. nidulans. In asexual spore formation, velB deletion strains show reduced number of conidia, and decreased and delayed mRNA accumulation of the key asexual regulatory genes brlA, abaA, and vosA. Overexpression of velB induces a two-fold increase of asexual spore production compared to wild type. Furthermore, the velB deletion mutant exhibits increased conidial germination rates in the presence of glucose, and rapid germination of conidia in the absence of external carbon sources. In vivo immuno-pull-down analyses reveal that VelB primarily interacts with VosA in both asexual and sexual spores, and VelB and VosA play an inter-dependent role in spore viability, focal trehalose biogenesis and control of conidial germination. Genetic and in vitro studies reveal that AbaA positively regulates velB and vosA mRNA expression during sporogenesis, and directly binds to the promoters of velB and vosA. In summary, VelB acts as a positive regulator of asexual development and regulates spore maturation, focal trehalose biogenesis and germination by interacting with VosA in A. nidulans.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aspergillus nidulans / metabolism*
  • Carrier Proteins / metabolism
  • Chromatography, Liquid / methods
  • Culture Media / chemistry
  • Fungal Proteins / chemistry*
  • Fungal Proteins / physiology*
  • Gene Deletion
  • Gene Expression Regulation, Fungal*
  • Nucleic Acids / chemistry
  • Oligonucleotides / genetics
  • RNA, Messenger / metabolism
  • Species Specificity
  • Spectrometry, Mass, Electrospray Ionization / methods
  • Spores, Fungal / physiology*
  • Tandem Mass Spectrometry / methods
  • Trehalose / chemistry

Substances

  • Carrier Proteins
  • Culture Media
  • Fungal Proteins
  • Nucleic Acids
  • Oligonucleotides
  • RNA, Messenger
  • Trehalose

Grants and funding

This work was supported by the National Science Foundation (IOS-0950850), USDA CSREES Hatch (WIS01195) and UW Food Research Institute grants to JHY. HSP was in part supported by the UW FRI Foster Award and Korea Research Foundation Grant funded by the Korea Government (MOEHRD) (KRF-2007-612-E00010). Y.H. Kim was supported by a grant of Korea Basic Science Institute (G30123). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.