title: Two genes encoding protein phosphatase 2A catalytic subunits are differentially expressed in rice.
abstract: Type 2A serine/threonine protein phosphatase (PP2A) plays a variety of regulatory roles in metabolism and signal transduction. Two closely related PP2A catalytic subunit (PP2Ac) genes, OsPP2A-1 and OsPP2A-3, have been isolated from the monocot Oryza sativa. Both genes contain six exons and five introns which intervene at identical locations, suggesting they have descended from a recent duplication event. Their encoded proteins share 97% sequence identity and are highly similar (94-96%) to a PP2Ac subfamily (AtPP2A-1, -2 and -5) identified in Arabidopsis thaliana. Both OsPP2A-1 and OsPP2A-3 are ubiquitously expressed, with the expression levels high in stems and flowers and low in leaves. OsPP2A-1, but not OsPP2A-3, is also highly expressed in roots. Transcript levels of OsPP2A-1 in roots and OsPP2A-3 in stems are elevated at the maturation and young stages, respectively. Drought and high salinity upregulate both genes in leaves, whereas heat stress represses OsPP2A-1 in stems and induces OsPP2A-3 in all organs. These findings indicate that the two PP2Ac genes are subjected to developmental and stress-related regulation. In situ hybridization results show that both transcripts exhibit nearly identical cellular distribution, except in leaves, and are abundant in meristematic tissues including the young leaf blade of stems and the root tip.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region, People's Republic of China.
authors.forename: Richard Man Kit
authors.initials: RM
authors.lastname: Yu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Zeng-Fu
authors.initials: ZF
authors.lastname: Xu
authors.forename: Mee-Len
authors.initials: ML
authors.lastname: Chye
authors.forename: Richard Yuen Chong
authors.initials: RY
authors.lastname: Kong
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D020134:Catalytic Domain / Q000235:genetics*; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D005091:Exons; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D017403:In Situ Hybridization; D007438:Introns; D007527:Isoenzymes / Q000235:genetics; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D010749:Phosphoprotein Phosphatases / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D054648:Protein Phosphatase 2; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D024363:Transcription Initiation Site
chemical_list: D018744:DNA, Plant; D007527:Isoenzymes; D012333:RNA, Messenger; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2