gene for the heat-shock protein HSP100 is induced by blue light and heat-shock in the fungus Phycomyces blakesleeanus

• Published in: Current genetics 2004-11, Vol.46 (5), p.295-303
• Main Authors: Rodriguez-Romero, J, Corrochano, L.M
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases - metabolism; adenosinetriphosphatase; Amino Acid Sequence; amino acid sequences; Bacterial Proteins; Base Sequence; Binding Sites; blue light; Carotenoids - biosynthesis; Carotenoids - radiation effects; Cloning, Molecular; gene expression; Gene Expression Regulation, Fungal - radiation effects; gene induction; Genes; heat shock elements; heat shock proteins; heat stress; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; Heat-Shock Response; High temperature; Hot Temperature; hspA gene; Light; Molecular Sequence Data; nucleotide sequences; Photoactivation; Photochemistry; Phycomyces; Phycomyces - chemistry; Phycomyces - radiation effects; Phycomyces blakesleeanus; promoter regions; Promoter Regions, Genetic - genetics; Proteins; Sequence Homology, Amino Acid; Transcription, Genetic
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/s00294-004-0534-4

We cloned and sequenced the Phycomyces hspA gene. The hspA gene product is a 901-amino-acid protein member of the clpB/HSP100 family. HSP100 proteins are ATPases involved in high-temperature tolerance, proteolysis, and protein disaggregation. Phycomyces HSP100 is composed of a domain presumably involved in protein-protein interactions and two ATP-binding domains. The hspA promoter contains three heat-shock elements that are presumably involved in the activation of hspA after heat-shock. In addition, four short sequences are present in the hspA promoter and in the promoter of the photoinducible genes carB and carRA; and these are candidates as binding sites for light-regulated transcription factors. Blue light can increase transcription of the hspA gene 10-fold, with a threshold of 1 J/m2. The threshold for hspA photoactivation is 10(4) times higher than the thresholds for blue-light regulation of sporangiophore development and photocarotenogenesis, which suggests that there are differences in the photosensory systems for gene photoactivation and mycelial photoresponses. A heat-shock of 30 min at 34 degrees C or 42 degrees C increased hspA gene activity 160-fold. The differences in maximum hspA gene transcription by blue light and heatshock suggest the presence of different regulatory mechanisms.