title: Differential expression of mepA, mepC and smtE during growth and development of Microbotryum violaceum.
abstract: Many fungi require a dimorphic switch from budding to filamentous growth to cause infection. Although the control of dimorphism has been elucidated for organisms such as Saccharomyces cerevisiae and Ustilago maydis, almost nothing is known about the control of mating and dimorphism in Microbotryum violaceum. M. violaceum mepA, mepC and smtE are homologs of genes whose encoded products act as, or interact with, components of the MAPK and cAMP-PKA pathways, conserved pathways that regulate mating and dimorphism in other fungi. A comparison of gene expression under various in vitro conditions was superimposed on a comparison of in vitro vs. in planta expression to yield a more complete picture of the expression of these genes in M. violaceum during fungal development. For the most part the expression of these genes was highest on low ammonium, intermediate for mated and in planta, and lowest on rich medium. As expected, under conditions of low ammonium, expression of the M. violaceum ammonium permease genes mepA and mepC mirrors that of S. cerevisiae MEP2 and U. maydis ump2. An intriguing possibility is that MepA is a sensor to signal when conditions are conducive for mating. The upregulation of smtE, which encodes a PAK kinase, suggests that the MAPK pathway regulates, at least partially, mating and might be linked to ammonium sensing/transport in M. violaceum.
authors.affiliation: Department of Biology, University of Louisville, Louisville, Kentucky 40292, USA.
authors.forename: Carolyn F
authors.initials: CF
authors.lastname: Hughes
authors.forename: Michael H
authors.initials: MH
authors.lastname: Perlin
mesh_terms: D001487:Basidiomycota / Q000235:genetics* / Q000254:growth & development*; D001692:Biological Transport / Q000235:genetics; D015152:Blotting, Northern; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D026901:Membrane Transport Proteins / Q000235:genetics; D010770:Phosphotransferases / Q000235:genetics; D000644:Quaternary Ammonium Compounds; D012331:RNA, Fungal / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D000644:Quaternary Ammonium Compounds; D012331:RNA, Fungal; D012333:RNA, Messenger; D010770:Phosphotransferases