Differential regulation of transcripts encoding cytosolic NADP-malic enzyme in C3 and C4 Flaveria species.
A cytosolic NADP-malic enzyme (CYTME) has been described previously in several plants, all C3 species. CYTME is distinct from the chloroplastic NADP-malic enzyme (CHLME) that is highly active in C4 species. We show that at least one CytMe gene is present in all Flaveria spp., including C3, C4, and C3-C4 intermediate types. Based on the CytMe expression patterns in Flaveria pringlei (C3) and Flaveria trinervia (C4), we suggest CYTME has several distinct roles, including the supplying of NADPH for cytosolic metabolism, the supporting of wound response or repair, and the balancing of cellular pH in illuminated leaves. These three roles are likely correlated with CytMe mRNAs of apparent sizes 2.0, 2.2, and 2.4 kb, respectively, which differ in the length of the 5' untranslated regions. Various regulatory mechanisms involving RNA processing and translational efficiency are discussed.
Lai
Lien B
LB
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA.
Tausta
S Lorraine
SL
Nelson
Timothy M
TM
D000222:Adaptation, Physiological; D019659:Asteraceae / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D002736:Chloroplasts / Q000201:enzymology; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D008291:Malate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
D018076:DNA, Complementary; D012333:RNA, Messenger; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)