bims-cytox1 Biomed News
on Cytochrome oxidase subunit 1
Issue of 2017‒06‒25
two papers selected by
Gavin McStay
New York Institute of Technology

  1. Trends Plant Sci. 2017 Jun 13. pii: S1360-1385(17)30117-6. [Epub ahead of print]
      Massive mitochondrial fusion (MMF) in germinating arabidopsis seeds, together with earlier studies, suggests a significant role for MMF in the life cycle of flowering plants. MMF is likely to facilitate nucleoid transmission, mitochondrial DNA (mtDNA) recombination, and the homogenization of mitochondrial components, thus providing a type of quality control for mitochondrial populations in new generations.
    Keywords:  massive mitochondrial fusion; mitochondria; mitochondria quality control; nucleoid transmission
  2. BMC Mol Biol. 2017 Jun 17. 18(1): 16
      BACKGROUND: Mitogenome diversity is staggering among early branching animals with respect to size, gene density, content and order, and number of tRNA genes, especially in cnidarians. This last point is of special interest as tRNA cleavage drives the maturation of mitochondrial mRNAs and is a primary mechanism for mt-RNA processing in animals. Mitochondrial RNA processing in non-bilaterian metazoans, some of which possess a single tRNA gene in their mitogenomes, is essentially unstudied despite its importance in understanding the evolution of mitochondrial transcription in animals.RESULTS: We characterized the mature mitochondrial mRNA transcripts in a species of the octocoral genus Sinularia (Alcyoniidae: Octocorallia), and defined precise boundaries of transcription units using different molecular methods. Most mt-mRNAs were polycistronic units containing two or three genes and 5' and/or 3' untranslated regions of varied length. The octocoral specific, mtDNA-encoded mismatch repair gene, the mtMutS, was found to undergo alternative polyadenylation, and exhibited differential expression of alternate transcripts suggesting a unique regulatory mechanism for this gene. In addition, a long noncoding RNA complementary to the ATP6 gene (lncATP6) potentially involved in antisense regulation was detected.
    CONCLUSIONS: Mt-mRNA processing in octocorals possessing a single mt-tRNA is complex. Considering the variety of mitogenome arrangements known in cnidarians, and in general among non-bilaterian metazoans, our findings provide a first glimpse into the complex mtDNA transcription, mt-mRNA processing, and regulation among early branching animals and represent a first step towards understanding its functional and evolutionary implications.
    Keywords:  Alternative polyadenylation (APA); Cnidaria; Long noncoding RNA (lncRNA); Mitochondrial RNA; Mitogenome; Non-bilaterian; Octocorals; Polycistronic transcripts; tRNA punctuation