Cloning and characterisation of a glutamate dehydrogenase cDNA from tomato (Lycopersicon esculentum L.).
A full-length cDNA (legdh1) has been cloned encoding glutamate dehydrogenase (GDH) from tomato (Lycopersicon esculentum L.). legdh1 is 1568 bp long and contains an open reading frame encoding a 44.8 kDa polypeptide with a putative mitochondrial-matrix-targeting pre-sequence at its N-terminus. Southern analysis indicates the existence of one copy of legdh1 per haploid genome, and no closely related genes were detected by Southern analysis at low stringency. We hypothesise that in tomato, the two GDH subunits may arise from post-transcriptional modifications of a single gene. Northern analysis reveals high expression of legdh1 in roots, lower levels of expression in stems, flowers and leaves, and no detectable expression in fruits. In general, there was no correlation between steady-state mRNA level and protein activity in the tissues analysed, again suggesting the importance of post-transcriptional events in the regulation of GDH. Comparison of cloned plant GDH proteins reveals a high degree of homology throughout the sequence except for a very specific, highly divergent region.
Purnell
M P
MP
Department of Botany, University of Queensland, Brisbane, Australia.
Stewart
G R
GR
Botella
J R
JR
D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D014644:Genetic Variation; D018745:Genome, Plant; D005969:Glutamate Dehydrogenase / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics*; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D018517:Plant Roots; D010944:Plants; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D018076:DNA, Complementary; D046911:Macromolecular Substances; D012333:RNA, Messenger; D011994:Recombinant Proteins; D005969:Glutamate Dehydrogenase