Open Access

The differential expression of ribosomal 18S RNA paralog genes from the chaetognath Spadella cephaloptera

  • Roxane-Marie Barthélémy1Email author,
  • Michel Grino2,
  • Pierre Pontarotti3,
  • Jean-Paul Casanova1 and
  • Eric Faure1
Cellular & Molecular Biology LettersAn International Journal200712:26

https://doi.org/10.2478/s11658-007-0026-x

Received: 15 January 2007

Accepted: 18 April 2007

Published: 24 June 2007

Abstract

Chaetognaths constitute a small marine phylum of approximately 120 species. Two classes of both 18S and 28S rRNA gene sequences have been evidenced in this phylum, even though significant intraindividual variation in the sequences of rRNA genes is unusual in animal genomes. These observations led to the hypothesis that this unusual genetic characteristic could play one or more physiological role(s). Using in situ hybridization on the frontal sections of the chaetognath Spadella cephaloptera, we found that the 18S Class I genes are expressed in the whole body, with a strong expression throughout the gut epithelium, whereas the expression of the 18S Class II genes is restricted to the oocytes. Our results could suggest that the paralog products of the 18S Class I genes are probably the “housekeeping” 18S rRNAs, whereas those of class II would only be essential in specific tissues. These results provide support for the idea that each type of 18S paralog is important for specific cellular functions and is under the control of selective factors.

Key words

18S Chaetognath Spadella cephaloptera In situ hybridization Duplication Expression pattern rRNA paralogs

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