title: Transcription profile of Trichophyton rubrum conidia grown on keratin reveals the induction of an adhesin-like protein gene with a tandem repeat pattern.
abstract: BACKGROUND
  Trichophyton rubrum is a cosmopolitan filamentous fungus that can infect human keratinized tissue (skin, nails and, rarely, hair) and is the major agent of all chronic and recurrent dermatophytoses. The dermatophyte infection process is initiated through the release of arthroconidial adhesin, which binds to the host stratum corneum. The conidia then germinate, and fungal hyphae invade keratinized skin structures through the secretion of proteases. Although arthroconidia play a central role in pathogenesis, little is known about the dormancy and germination of T. rubrum conidia and the initiation of infection. The objective of this study was to evaluate the transcriptional gene expression profile of T. rubrum conidia during growth on keratin- or elastin-containing medium, mimicking superficial and deep dermatophytosis, respectively.
  
  
  RESULTS
  A transcriptional profiling analysis was conducted using a custom oligonucleotide-based microarray by comparing T. rubrum conidia grown on elastin and keratin substrates. This comparison shows differences according to protein source used, but consisted of a very small set of genes, which could be attributed to the quiescent status of conidia. The modulated genes were related to the dormancy, survival and germination of conidia, including genes involved in the respiratory chain, signal transduction and lipid metabolism. However, an induction of a great number of proteases occurred when T. rubrum was grown in the presence of keratin such as the subtilisin family of proteases (Sub 1 and Sub 3) and leucine aminopeptidase (Lap 1 and Lap 2). Interestingly, keratin also promoted the up-regulation of a gene encoding an adhesin-like protein with a tandem repeat sequence. In silico analysis showed that the protein contains a domain related to adhesin that may play a role in host-pathogen interactions. The expression of this adhesin-like gene was also induced during the co-culture of T. rubrum with a human keratinocyte cell line, confirming its role in fungal-host interactions.
  
  
  CONCLUSIONS
  These results contribute to the discovery of new targets involved in the adhesion of conidia and the maintenance of conidial dormancy, which are essential for triggering the process of infection and the chronicity of dermatophytosis.
authors.affiliation: Unidade de Biotecnologia, Universidade de Ribeirão Preto, Av: Costábile Romano 2201, 14096-900, Ribeirão Preto, SP, Brazil.
authors.forename: Tamires Aparecida
authors.initials: TA
authors.lastname: Bitencourt
authors.affiliation: Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, Brazil.
authors.forename: Claudia
authors.initials: C
authors.lastname: Macedo
authors.affiliation: Unidade de Biotecnologia, Universidade de Ribeirão Preto, Av: Costábile Romano 2201, 14096-900, Ribeirão Preto, SP, Brazil.|Instituto Federal do Sul de Minas - Campus Machado, Machado, Brazil.
authors.forename: Matheus Eloy
authors.initials: ME
authors.lastname: Franco
authors.affiliation: Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, Brazil.
authors.forename: Amanda Freire
authors.initials: AF
authors.lastname: Assis
authors.affiliation: Unidade de Biotecnologia, Universidade de Ribeirão Preto, Av: Costábile Romano 2201, 14096-900, Ribeirão Preto, SP, Brazil.
authors.forename: Tatiana Takahasi
authors.initials: TT
authors.lastname: Komoto
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Ribeirão Preto, Brazil.
authors.forename: Eliana Guedes
authors.initials: EG
authors.lastname: Stehling
authors.affiliation: Unidade de Biotecnologia, Universidade de Ribeirão Preto, Av: Costábile Romano 2201, 14096-900, Ribeirão Preto, SP, Brazil.
authors.forename: Rene Oliveira
authors.initials: RO
authors.lastname: Beleboni
authors.affiliation: Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de São Carlos, São Carlos, Brazil.
authors.forename: Iran
authors.initials: I
authors.lastname: Malavazi
authors.affiliation: Unidade de Biotecnologia, Universidade de Ribeirão Preto, Av: Costábile Romano 2201, 14096-900, Ribeirão Preto, SP, Brazil.
authors.forename: Mozart
authors.initials: M
authors.lastname: Marins
authors.affiliation: Unidade de Biotecnologia, Universidade de Ribeirão Preto, Av: Costábile Romano 2201, 14096-900, Ribeirão Preto, SP, Brazil. afachin@unaerp.br.
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: Fachin
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D018920:Coculture Techniques; D003470:Culture Media / Q000737:chemistry; D004549:Elastin / Q000737:chemistry; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D054884:Host-Pathogen Interactions; D006801:Humans; D015603:Keratinocytes; D007633:Keratins / Q000737:chemistry; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D013172:Spores, Fungal / Q000235:genetics*; D014005:Tinea / Q000382:microbiology; D059467:Transcriptome; D014249:Trichophyton / Q000235:genetics* / Q000472:pathogenicity
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D007633:Keratins; D004549:Elastin
keywords: Adhesin-like protein; Conidia; Elastin; Keratin; Transcriptional gene expression; Trichophyton rubrum