H-protein of the glycine cleavage system in Flaveria: alternative splicing of the pre-mRNA occurs exclusively in advanced C4 species of the genus.
A recent paper reports on the occurrence of alternative splicing of H-protein pre-mRNA in the C4 species, Flaveria trinervia, that is organ-specifically regulated. The analysis of 11 other species of the genus, F. cronquistii and F. pringlei (C3), F. anomala, F. chloraefolia, F. floridana, F. linearis and F. pubescens (C3-C4 intermediate), F. brownii (C4-like), F. palmeri, F. bidentis and F. australasica (C4), revealed that this post-transcriptional effect is not specific for F. trinervia. It occurs in all the examined C4 species of the genus Flaveria except the less advanced C4-like species, F. brownii. Both the position and the direct effect of alternative splicing, the addition of two alanine residues near to the N-terminus of the derived mature H-protein, are invariant. A quantification of the relative amounts of both transcripts revealed that, as in F. trinervia, the alternative mRNA strongly dominates in leaves. In sharp contrast, none of the C3, C3-C4 intermediate, or C4-like species showed alternative splicing. By Western analysis both H-isoproteins have been detected in F. trinervia and their ratio approximately corresponds to the measured transcript levels. It is concluded that alternative splicing leads to the synthesis of two different H-proteins of the glycine cleavage system in all advanced Flaveria C4 species.
Kopriva
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Department of Molecular Cell Biology, Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany.
Chu
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Bauwe
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D017398:Alternative Splicing; D000594:Amino Acid Oxidoreductases; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D050961:Glycine Decarboxylase Complex H-Protein; D050841:Glycine Dehydrogenase (Decarboxylating); D008969:Molecular Sequence Data; D009928:Organ Specificity; D010944:Plants / Q000145:classification / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism*; D013045:Species Specificity
D002352:Carrier Proteins; D018076:DNA, Complementary; D018744:DNA, Plant; D050961:Glycine Decarboxylase Complex H-Protein; D012322:RNA Precursors; D018749:RNA, Plant; D000594:Amino Acid Oxidoreductases; D050841:Glycine Dehydrogenase (Decarboxylating)