The S7 ribosomal protein gene is truncated and overlaps a cytochrome c biogenesis gene in pea mitochondria.
The pea mitochondrial genome contains a truncated rps7 gene lacking ca. 40 codons at its 5' terminus. This single-copy sequence is immediately downstream of and slightly overlapping an actively transcribed and edited reading frame of 744 bp (designated ccb248) homologous to the bacterial helC gene which encodes a subunit of the ABC-type heme transporter involved in cytochrome c biogenesis. This region of mitochondrial DNA appears recombinogenic, and the carboxy-termini of helC-type proteins are predicted to vary in sequence and length among plants. Sequences corresponding to the 5' coding region of rps7 were not detected elsewhere in the pea mitochondrial genome using wheat rps7 probes, and only a very short internal rps7 segment was observed in soybean mitochondrial DNA. The presence of rps7-homologous sequences in the nuclear genomes of pea and soybean is consistent with the recent transfer of a functional mitochondrial rps7 gene to the nucleus in certain plant lineages.
Biology Department, University of Ottawa, Canada.
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Zhuo
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Nguyen-Lowe
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Subramanian
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Bonen
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D002467:Cell Nucleus / Q000235:genetics; D003574:Cytochrome c Group / Q000235:genetics*; D019143:Evolution, Molecular; D018628:Gene Dosage; D017343:Genes, Plant; D008928:Mitochondria / Q000235:genetics*; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000235:genetics*; D017393:RNA Editing; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D011995:Recombination, Genetic; D012269:Ribosomal Proteins / Q000235:genetics*; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013025:Glycine max / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D003574:Cytochrome c Group; C112242:HelC protein, bacteria; D012333:RNA, Messenger; D018749:RNA, Plant; D012269:Ribosomal Proteins; C037442:ribosomal protein S7