Premium
veA ‐dependent RNA‐pol II transcription elongation factor‐like protein, RtfA, is associated with secondary metabolism and morphological development in Aspergillus nidulans
Author(s) -
Ramamoorthy Vellaisamy,
Shantappa Sourabha,
Dhingra Sourabh,
Calvo Ana M.
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.08142.x
Subject(s) - aspergillus nidulans , biology , gene , secondary metabolism , mutant , conidiation , genetics , transposable element , microbiology and biotechnology , biosynthesis
Summary In Aspergillus nidulans the global regulatory gene veA is necessary for the biosynthesis of several secondary metabolites, including the mycotoxin sterigmatocystin (ST). In order to identify additional veA ‐dependent genetic elements involved in regulating ST production, we performed a mutagenesis on a deletion veA (Δ veA ) strain to obtain revertant mutants (RM) that regained the capability to produce toxin. Genetic analysis and molecular characterization of one of the revertant mutants, RM3, revealed that a point mutation occurred at the coding region of the rtfA gene, encoding a RNA‐pol II transcription elongation factor‐like protein, similar to Saccharomyces cerevisiae Rtf1. The A. nidulans rtfA gene product accumulates in nuclei. Deletion of rtfA gene in a Δ veA background restored mycotoxin production in a medium‐dependent manner. rtfA also affects the production of other metabolites including penicillin. Biosynthesis of this antibiotic decreased in the absence of rtfA . Furthermore, rtfA is necessary for normal morphological development. Deletion of the rtfA gene in wild‐type strains ( veA +) resulted in a slight decrease in growth rate, drastic reduction in conidiation, and complete loss of sexual development. This is the first study of an Rtf1 like gene in filamentous fungi. We found rtfA putative orthologues extensively conserved in numerous fungal species.