RNA interference in formation of the somatic genome of ciliates Paramecium and Tetrahymena

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Abstract

Ciliates are the model of choice to study RNA interference, the mechanism playing key role in biology of these protists. The genome scanning processes of two ciliates, Tetrahymena and Paramecium (Oligohymenophorea), leading to formation of the somatic genome from the chromosomes of the generative nucleus are compared in the review. Matching of several simulta neously present in one cell genomes is mediated by small RNAs and results in precise reproduction of maternal somatic genome in the sexual progeny.

About the authors

Irina V. Nekrasova

Saint Petersburg State University

Email: ne-irina@yandex.ru

Associate Professor, Faculty of Biology

Russian Federation, 7/9, Universitetskaya embankment, Saint-Petersburg, 199034

Alexey A. Potekhin

Saint Petersburg State University

Author for correspondence.
Email: alexey.potekhin@spbu.ru
ORCID iD: 0000-0003-4162-5923
ResearcherId: K-3633-2013

Professor, Faculty of Biology

Russian Federation, 7/9, Universitetskaya embankment, Saint-Petersburg, 199034

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2. Fig. 1. Genome scanning process in Paramecium (A) and Tetrahymena (B).

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3. Fig. 2. Small RNAs acting in genome scanning in Paramecium and Tetrahymena. In Paramecium these are scanRNAs produced by Dcl2/3p, and iesRNAs produced by Dcl5p in the amplification loop. In Tetrahymena early and late scanRNAs are formed by Dcl1p

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4. Fig. 3. Expression periods of the PIWI proteins in life cycles of Paramecium and Tetrahymena. MIC(s) of each conjugating cell passes meiosis (R!), and all haploid nuclei except one get degraded. Remaining nucleus passes mitosis (M) leading to formation of two haploid pronuclei. One of pronuclei of each cell migrates to the partner cell and fuses with the stationary pronucleus of that cell. Zygotic nucleus, synkaryon, then divides mitotically (also labeled M)

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Copyright (c) 2018 Nekrasova I.V., Potekhin A.A.

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