title: In silico identification and characterization of the MAPK family members of unicellular model eukaryote Tetrahymena thermophila.
abstract: The biological function and evolutionary diversity of the mitogen-activated protein kinase (MAPK) family have mostly been studied in fungi, animals and plants, with very limited information from lower eukaryotes. This study aimed to describe the MAPKs of unicellular Tetrahymena thermophila. Eight members of the T. thermophila MAPK (TtMPK) gene family, in addition to previously reported TtMPK1, TtMPK2 and TtMPK3, were identified bioinformatically using a T. thermophila genome database. Phylogenetic analysis assigned the TtMPKs into two major groups, ERK1/2-like (TtMPK1, 2, 3, 5, 6, 7, 8, and 9) as stress-responsive MAPKs for biotic and abiotic stresses, and ERK7/8-like (TtMPK4, 10, and 11) as cell-cycle-associated protein kinases for biotic factors. Semi-quantitative RT-PCR analysis of the TtMPKs showed high mRNA expression at 30°C; however, only TtMPK5 and TtMPK6 showed high expression at 37°C. Osmotic shock by 100mM NaCl only increased the expression of TtMPK2, whereas 20mM NaCl reduced the expression of all MPKs to almost zero. The results suggested that T. thermophila MAPKs are among the closest representatives of the ancestors of the eukaryotic MAPK family. Although no functional characterization of MPKs was performed, this study is the first report of the genome-wide MAPK family in T. thermophila.
authors.affiliation: Fatih University, Faculty of Sciences, Department of Biology, Buyukcekmece Campus, 34500 Istanbul, Turkey. Electronic address: mtahay@gmail.com.
authors.forename: Mehmet Taha
authors.initials: MT
authors.lastname: Yıldız
authors.affiliation: Anadolu University, Faculty of Sciences, Department of Biology, Yunusemre Campus, 26470 Eskisehir, Turkey. Electronic address: marslanyolu@anadolu.edu.tr.
authors.forename: Muhittin
authors.initials: M
authors.lastname: Arslanyolu
mesh_terms: D000595:Amino Acid Sequence; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D040081:Protein Array Analysis; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000235:genetics; D016808:Tetrahymena thermophila / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*
chemical_list: D012965:Sodium Chloride; D020928:Mitogen-Activated Protein Kinases
keywords: In silico; MAPK; Protista; Stress; Tetrahymena thermophila; mRNA expression profile