IBB PAS Repository

High coding density on the largest Paramecium tetraurelia somatic chromosome.

Zagulski, Marek and Nowak, Jacek K. and Le Mouël, Anne and Nowacki, Mariusz and Migdalski, Andrzej and Gromadka, Robert and Noël, Benjamin and Blanc, Isabelle and Dessen, Philippe and Wincker, Patrick and Keller, Anne-Marie and Cohen, Jean and Meyer, Eric and Sperling, Linda (2004) High coding density on the largest Paramecium tetraurelia somatic chromosome. Current biology : CB, 14 (15). pp. 1397-404. ISSN 0960-9822

Full text not available from this repository.


Paramecium, like other ciliates, remodels its entire germline genome at each sexual generation to produce a somatic genome stripped of transposons and other multicopy elements. The germline chromosomes are fragmented by a DNA elimination process that targets heterochromatin to give a reproducible set of some 200 linear molecules 50 kb to 1 Mb in size. These chromosomes are maintained at a ploidy of 800n in the somatic macronucleus and assure all gene expression. We isolated and sequenced the largest megabase somatic chromosome in order to explore its organization and gene content. The AT-rich (72%) chromosome is compact, with very small introns (average size 25 nt), short intergenic regions (median size 202 nt), and a coding density of at least 74%, higher than that reported for budding yeast (70%) or any other free-living eukaryote. Similarity to known proteins could be detected for 57% of the 460 potential protein coding genes. Thirty-two of the proteins are shared with vertebrates but absent from yeast, consistent with the morphogenetic complexity of Paramecium, a long-standing model for differentiated functions shared with metazoans but often absent from simpler eukaryotes. Extrapolation to the whole genome suggests that Paramecium has at least 30,000 genes.

Item Type:Article
Subjects:Q Science > QR Microbiology
Divisions:Laboratory of DNA Sequencing and Oligonucleotide Synthesis
ID Code:35
Deposited By: Robert Gromadka
Deposited On:03 Apr 2013 09:03
Last Modified:05 Oct 2015 08:19

Repository Staff Only: item control page