Penicillium marneffei actin expression during phase transition, oxidative stress, and macrophage infection

• Published in: Molecular biology reports 2011-04, Vol.38 (4), p.2813-2819
• Main Authors: Kummasook, Aksarakorn, Tzarphmaag, Ariya, Thirach, Sophit, Pongpom, Monsicha, Cooper, Chester R. Jr, Vanittanakom, Nongnuch
• Format: Article
• Language: English
• Subjects: ActA protein; Actin; Actins - genetics; Adaptation, Physiological - physiology; Amino Acid Sequence; amino acid sequences; Amino acids; Animal Anatomy; Animal Biochemistry; Aspergillus clavatus; Aspergillus nidulans; Base Sequence; Biomedical and Life Sciences; Blotting, Northern; Cell culture; Conidia; Developmental stages; Dimorphism; DNA Primers - genetics; Environmental stress; Fungi; gene expression regulation; Gene Expression Regulation, Fungal - physiology; genes; germ tube; Germ tubes; Histology; Infection; Life Sciences; Macrophages; Molecular biology; Molecular Sequence Data; Morphology; Mycelia; mycelium; Northern blotting; Opportunist infection; Oxidative stress; Pathogens; Penicillium; Penicillium - genetics; Penicillium - metabolism; Penicillium - physiology; Penicillium marneffei; Phase transition; Proteins; Schizosaccharomyces pombe; Sequence Analysis, DNA; Species Specificity; Stress response; Temperature; Temperature effects; yeasts
• ISSN: 0301-4851; 1573-4978
• DOI: 10.1007/s11033-010-0427-1

Penicillium marneffei is an opportunistic fungal pathogen that exhibits thermally regulated dimorphism. At 25°C, this fungus grows vegetatively as mycelia, but at 37°C or upon invasion of a host, a fission yeast form is established. Yet, despite increased numbers of molecular studies involving this fungus, the role of P. marneffei stress response-related proteins is not well characterized. Actin is one of the proteins that have been proposed to play a role not only in cell transition, but also in thermo-adaptation. Here, we report the isolation and characterization of the actin encoding gene, actA, from P. marneffei. Examination of the deduced amino acid sequence of the ActA protein revealed that it is closely related to Aspergillus nidulans and Aspergillus clavatus. Northern blot analysis of actin expression during the mycelium to yeast phase transition of P. marneffei showed that the actA transcripts were initially upregulated soon after shifting the incubation temperature from 25°C to 37°C, but subsequently decreased slightly and did not change during further growth or under stress conditions. When cultures were started with conidia, upregulation of actA gene was found to correlate with germ tube production at either 25°C or 37°C. However, the relative expression level of actA transcripts again showed no significant differences in different cell types (conidia, mycelium, and yeast cells) or during macrophage infection. These results suggest that actin may play an important role in the early stages of cellular development, but not in environmental stress responses.