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DNA repair in sea star asterias rubens: genomic aspects

Michel Leclerc

1556 rue Isabelle Romée , Sandillon 45640, France

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

DOI: 10.15761/HCE.1000102

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Both genetic and biochemical approaches have been used, to study the molecular mechanisms, by which damaged DNA is repaired, in a number of species. The fundamental DNA repair pathways have been functionally conserved for the most part among, prokaryotes, lower eukaryotes and higher eukaryotes. The proteins and protein families, involved, in these repair processes, show high degrees of amino-acid sequence conservation. However, there are also a number of cases  in which lack of conservation of particular polypeptides may reveal interesting species specific differences in how certain repair functions are performed.

  1. DNA methylation:  In mammals,  DNA methylation is associated with the regulation of gene expression and the maintenance of the differential state in cell lineages [1]. It is also present in other phylogenetic

 groups such as some invertebrates: sponges, some insects, sea urchins.

  1. DNA repair in Invertebrates: The recent completion of the Drosophila genome sequence  show the existence of the

 Rad 51 Family DNA repair

(Rad 51 named for Saccharomyces cerevisiae: the first member discovered). Two Drosophila Rad 51 have been described [2]: there are important in both recombinational DNA repair and meiotic recombination.

  1. DNA repair in sea star Asterias rubens:  Sea star Asterias rubens genome has recently been studied [3] in immunized and non-immunized sea stars to HRP (Horse-radish peroxydase)

We  find Rad 51 Family DNA repair and also what is original and not yet described ,genes which are found in vertebrates exclusively:

  1. in non-immunized sea star genome ("control")
  2. Control:TR38504|c0_g1_i1    sp|Q64267|XPA_MOUSE DNA repair protein complementing XP-A cells homolog OS=Mus musculus GN=Xpa PE=1 SV=2
    Control:Contig11913    sp|P23475|XRCC6_MOUSE X-ray repair cross-complementing protein 6 OS=Mus musculus GN=Xrcc6 PE=1 SV=5

    Control:Contig7953    sp|P27641|XRCC5_MOUSE X-ray repair cross-complementing protein 5 OS=Mus musculus GN=Xrcc5 PE=2 SV=4

  3. We find similar results in immunized sea star genome.
  4. Interpretation -Discussion:

 These genes are mainly used in cellular response to X-Ray, to gamma radiation, in Vertebrates.It is surprising to find them in an  ancestral invertebrate: the sea star Asterias rubens: The enigmatic sea star!

Another explication can be done. These genes named : Xrcc6 and Xrrc5  play a role in the immune process in which immune receptor V,D and J,orV and J gene segments, depending on the specific receptor are recombined within a single locus utilizing the conserved heptamer and nonomer recombination signal sequence (RSS) regional genes (V,D,J) used to generate Ig molecules.

This last aspect of  sea star genomic studies corroborates the existence of the sea star primitive antibody.

References

  1. Riggs AD  (1990) DNA methylation and late replication probably aid cell memory, and type I DNA reeling could aid chromosome folding and enhancer function. Philos Trans R Soc Lond B Biol Sci  326: 285-297. [Crossref]
  2. McKee BD (1996) Chromosoma 104: 479-488.
  3. Leclerc M (2011) Immunol Lett  138: 197-198.

Article Type

Short Communication

Publication history

Received date: December 13 2016
Accepted date: January 20, 2017
Published date: January 24, 2017

Copyright

© 2016 Leclerc M. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation

Leclerc M(2017) DNA repair in sea star asterias rubens: genomic aspects. Histol Cytol Embryol 1: DOI: 10.15761/HCE.1000102

Corresponding author

Michel Leclerc

556 rue Isabelle Romée, Sandillon 45640, France

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