Molecular characterization of a phosphoenolpyruvate carboxylase in the gymnosperm Picea abies (Norway spruce).
Phosphoenolpyruvate carboxylase (PEPC) genes and cDNA sequences have so far been isolated from a broad range of angiosperm but not from gymnosperm species. We constructed a cDNA library from seedlings of Norway spruce (Picea abies) and identified cDNAs coding for PEPC. A full-length PEPC cDNA was sequenced. It consists of 3522 nucleotides and has an open reading frame (ORF) that encodes a polypeptide (963 amino acids) with a molecular mass of 109551. The deduced amino acid sequence revealed a higher similarity to the C3-form PEPC of angiosperm species (86-88%) than to the CAM and C4 forms (76-84%). The putative motif (Lys/Arg-X-X-Ser) for serine kinase, which is conserved in all angiosperm PEPCs analysed so far, is also present in this gymnosperm sequence. Southern blot analysis of spruce genomic DNA under low-stringency conditions using the PEPC cDNA as a hybridization probe showed a complex hybridization pattern, indicating the presence of additional PEPC-related sequences in the genome of the spruce. In contrast, the probe hybridized to only a few bands under high-stringency conditions. Whereas this PEPC gene is highly expressed in roots of seedlings, a low-level expression can be detected in cotyledons and adult needles. A molecular phyiogeny of plant PEPC including the spruce PEPC sequence revealed that the spruce PEPC sequence is clustered with monocot and dicot C3- form PEPCs including the only dicot C4 form characterized so far.
Relle
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Institut für Allgemeine Botanik der Johannes Gutenberg-Universität Mainz, Germany.
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D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010730:Phosphoenolpyruvate Carboxylase / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D011487:Protein Conformation; D012333:RNA, Messenger / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000145:classification / Q000201:enzymology* / Q000235:genetics
D018076:DNA, Complementary; D018744:DNA, Plant; D012333:RNA, Messenger; D010730:Phosphoenolpyruvate Carboxylase