Transcriptomic analysis of the exit from dormancy of Aspergillus fumigatus conidia
1 Unité des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
2 Plateforme Biopuces, UMR 5504 & 792 d'Ingenierie des Systèmes Biologiques et Procédés, INSA-CNRS-INRA, 135 Avenue de Rangueil, 31077 Toulouse Cedex 04, France
3 Plate-forme Puces à ADN, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
4 Laboratoire de Génomique des Microorganismes Pathogènes, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
5 Unité de Biologie et Génétique du Paludisme, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
BMC Genomics 2008, 9:417 doi:10.1186/1471-2164-9-417Published: 16 September 2008
Establishment of aspergillosis is depending upon the exit from dormancy and germination of the conidia of Aspergillus fumigatus in the lung. To gain an understanding of the molecular mechanisms underlying the early steps of conidial germination, we undertook a transcriptomic analysis using macroarrays constructed with PCR fragments from > 3,000 genes (around one third of the annotated A. fumigatus genome).
Major results of this analysis are the following: (i) conidia stored pre-packaged mRNAs transcripts (27% of genes have transcripts in the resting conidia; (ii) incubation at 37°C in a nutritive medium induced up- and down-regulation of genes: 19% of the total number of genes deposited on the array were up-regulated whereas 22% of the genes with pre-packaged mRNA in the resting conidia were down-regulated; (iii) most modifications were seen during the first 30 min of germination whereas very little modification of gene expression occurred during the following hour; (iv) one-year old conidia and one-week old conidia behaved similarly at transcriptional level.
Transcriptomic data indicate that the exit from dormancy is associated with a shift from a fermentative metabolism to a respiratory metabolism as well as a trend toward immediate protein synthesis.