catA, a new Aspergillus nidulans gene encoding a developmentally regulated catalase

Aspergillus nidulans asexual sporulation (conidiation) is a model system for studying gene regulation and development. The CAN5 cDNA is one of several clones isolated based on transcript induction during conidiation. Here we present the molecular characterization of its corresponding gene, demonstra...

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Bibliographic Details
Published in:Current genetics 1996-03, Vol.29 (4), p.352-359
Main Authors: Navarro, R.E, Stringer, M.A, Hansberg, W, Timberlake, W.E, Aguirre, J. (Universidad Nacional Autonoma de Mexico (Mexico). Dept. de Microbiologia. Inst. de Fisiologia Celular)
Format: Article
Language:English
Subjects:
Amino Acid Sequence
ASPERGILLUS NIDULANS
Aspergillus nidulans - genetics
Base Sequence
CATALASA
CATALASE
Catalase - genetics
ESPORULACION
ESTRES
Gene Expression Regulation, Developmental
Genes, Fungal
Molecular Sequence Data
OXIDACION
OXIDATION
OXYDATION
RNA, Messenger - genetics
SPORULATION
STRESS
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Summary:Aspergillus nidulans asexual sporulation (conidiation) is a model system for studying gene regulation and development. The CAN5 cDNA is one of several clones isolated based on transcript induction during conidiation. Here we present the molecular characterization of its corresponding gene, demonstrating that it encodes a developmentally regulated catalase, designated catA. The catA 744-amino-acid-residue polypeptide shows significant identity to other catalases. Its similarity to prokaryotic catalases is greater than to other fungal catalases. catA mRNA is barely detectable in growing mycelia, highly induced during sporulation, and present in isolated spores. However, catA expression is not dependent on the developmental regulatory genes brlA, abaA and wetA. Direct catalase activity determination in native gels revealed the existence of two bands of activity. One of these bands represented the major activity during vegetative growth and was induced during sporulation. The second catalase activity appeared after the induction of sporulation and was the predominant activity in spores. Disruption of catA abolished the major spore catalase without eliminating the vegetative activity, indicating the existence of at least two catalase genes in A. nidulans. catA-disrupted mutants produced spores that were sensitive to H2O2, as compared to wild-type spores. The increase in the activity of the vegetative catalase and the appearance of a second catalase during asexual sporulation is consistent with the occurrence of an oxidative stress during development.
ISSN:0172-8083
1432-0983
DOI:10.1007/s002940050056