title: Possible involvement of differential splicing in regulation of the activity of Arabidopsis ANP1 that is related to mitogen-activated protein kinase kinase kinases (MAPKKKs).
abstract: Three types of Arabidopsis cDNA (cANP1, cANP2 and cANP3) have been isolated that encode putative protein kinases, designated ANP1, ANP2 and ANP3. These kinases exhibit a high degree of homology to NPK1, a tobacco protein that is a member of the family of mitogen-activated protein kinase kinase kinases (MAPKKKs), which appears to function in the proliferation of tobacco cells. The predicted amino acid sequences of the kinase domains in the amino-terminal halves of the ANPs were more than 80% identical to that of NPK1, while the kinase-unrelated regions in the carboxy-terminal halves exhibited relatively low homology. Two species of cANP1 were identified, ANP1L cDNA (cANP1L) and ANP1S cDNA (cANP1S), which were derived from a single ANP1 gene: the former had an intron-like sequence in the coding region for the kinase-unrelated region, while the latter did not include such an intron-like sequence. cANP1L encoded a putative protein with both kinase and kinase-unrelated domains, resembling NPK1, whereas cANP1S encoded only the amino-terminal kinase domain because the intron-like sequence was absent, with resulting elimination of most of the kinase-unrelated region. Genetic analysis with mutant yeast cells showed that over-expression of cANP1L or of cANP1S activated the mating pheromone-responsive signal pathway which is mediated by a MAP kinase cascade. Moreover, the extent of such activation by cANP1S was greater than that by cANP1L. These results predict that differential splicing of the intron-like sequence in the ANP1 transcript might be at least one of the molecular mechanisms involved in the generation of active ANP1 protein kinase.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Nishihama
authors.forename: H
authors.initials: H
authors.lastname: Banno
authors.forename: E
authors.initials: E
authors.lastname: Kawahara
authors.forename: K
authors.initials: K
authors.lastname: Irie
authors.forename: Y
authors.initials: Y
authors.lastname: Machida
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D010947:Plants, Toxic; D011494:Protein Kinases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D011994:Recombinant Proteins; D011494:Protein Kinases; C000602234:ANP2 protein, Arabidopsis; C000602235:ANP3 protein, Arabidopsis; D020930:MAP Kinase Kinase Kinases