Molecular cloning and characterization of two phosphatase 2A catalytic subunit genes from Arabidopsis thaliana.
The plant Arabidopsis thaliana contains five isoforms of the catalytic subunit of protein phosphatase 2A (PP2A) that can be grouped into two families, one composed by isoforms PP2A-1, -2 and -5 and the other composed by isoforms PP2A-3 and PP2A-4. An Arabidopsis genomic library was screened and several clones corresponding to genes PP2A-3 and PP2A-4 were isolated and analysed. Both genes span over approximately 4.5kbp and are composed of 11 exons and 10 introns that show identical organization. Their untranslated regions are also highly conserved, suggesting that the two genes derive from a common ancestral gene. However, the position of intron/exon junctions completely differs from that of the human PP2A genes. Two transcription start sites have been found in the PP2A-3 gene, the major one mapping at nucleotide position -188 from the translation start codon, whereas only one is observed in PP2A-4 (-145). Functional gene promoter analysis reveals that elements required for transient expression of PP2A-3 and PP2A-4 on a protoplast system are contained within a region of about 600bp upstream from the transcription start sites. This is the first report on the cloning and characterization of genes encoding catalytic subunits of Ser/Thr protein phosphatases 2A in higher plants.
Pérez-Callejón
E
E
Unitat de Bioquímica, Facultat de Farmacia, Universitat de Barcelona, Pça. Pius XII s/n, Barcelona 08028, Spain.
Casamayor
A
A
Pujol
G
G
Camps
M
M
Ferrer
A
A
Ariño
J
J
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D005091:Exons; D017343:Genes, Plant; D015698:Genomic Library; D006801:Humans; D007438:Introns; D007527:Isoenzymes / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction; D054648:Protein Phosphatase 2; D011523:Protoplasts; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D017931:DNA Primers; D007527:Isoenzymes; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2