title: Evidence of cAMP involvement in cellobiohydrolase expression and secretion by Trichoderma reesei in presence of the inducer sophorose.
abstract: BACKGROUND
  The signaling second messenger cyclic AMP (cAMP) regulates many aspects of cellular function in all organisms. Previous studies have suggested a role for cAMP in the regulation of gene expression of cellulolytic enzymes in Trichoderma reesei (anamorph of Hypocrea jecorina).
  
  
  METHODS
  The effects of cAMP in T. reesei were analyzed through both activity and expression of cellulase, intracellular cAMP level measurement, western blotting, indirect immunofluorescence and confocal microscopy.
  
  
  RESULTS
  To elucidate the involvement of cAMP in the cellulase expression, we analyzed the growth of the mutant strain ∆acy1 and its parental strain QM9414 in the presence of the inducers cellulose, cellobiose, lactose, or sophorose, and the repressor glucose. Our results indicated that cAMP regulates the expression of cellulase in a carbon source-dependent manner. The expression cel7a, and cel6a genes was higher in the presence of sophorose than in the presence of cellulose, lactose, cellobiose, or glucose. Moreover, intracellular levels of cAMP were up to four times higher in the presence of sophorose compared to other carbon sources. Concomitantly, our immunofluorescence microscopy and western blot data suggest that in the presence of sophorose, cAMP may regulate secretion of cellulolytic enzymes in T. reesei.
  
  
  CONCLUSIONS
  These results allow us to better understand the role of cAMP and expand our knowledge on the signal transduction pathways involved in the regulation of cellulase expression in T. reesei. Finally, our data may help develop new strategies to improve the expression of cel7a and cel6a genes, and therefore, favor their application in several biotechnology fields.
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. karolmvnogueira@hotmail.com.
authors.forename: Karoline Maria Vieira
authors.initials: KM
authors.lastname: Nogueira
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. mari.ncosta@hotmail.com.
authors.forename: Mariana do Nascimento
authors.initials: Mdo N
authors.lastname: Costa
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. renatocbufes@yahoo.com.br.
authors.forename: Renato Graciano
authors.initials: RG
authors.lastname: de Paula
authors.affiliation: Department of Cell Biology and Molecular and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. flavia.bioquimica@gmail.com.
authors.forename: Flávia Costa
authors.initials: FC
authors.lastname: Mendonça-Natividade
authors.affiliation: Department of Cell Biology and Molecular and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. ricciazevedor@usp.br.
authors.forename: Rafael
authors.initials: R
authors.lastname: Ricci-Azevedo
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. rsilva@fmrp.usp.br.
authors.forename: Roberto Nascimento
authors.initials: RN
authors.lastname: Silva
mesh_terms: D015153:Blotting, Western; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000096:biosynthesis* / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D005936:Glucans / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D014242:Trichoderma / Q000235:genetics / Q000378:metabolism*
chemical_list: D005936:Glucans; D000242:Cyclic AMP; D043366:Cellulose 1,4-beta-Cellobiosidase; C003328:sophorose