Epigenetic Chromatin Regulation
Kazufumi MOCHIZUKI
IGH - UMR 9004
141, rue de la Cardonille, 34396 Montpellier
Phone: +33 4 34 35 99 18
Email: kazufumi.mochizuki@igh.cnrs.fr
Transposable elements are molecular parasites that are able to move from one genome position to another. Cells in our body have a mechanism to silence these potentially harmful elements: locking transposable element into a closed form chromatin, called heterochromatin. Chemically, both transposable elements and the other parts of the genome are just stretches of DNA. So, how can cells distinguish junk from precious DNA? Evidence suggests that small RNAs, ~20-30 nucleotides in length, act as security guards to identify transposable elements. However, much remains unknown about how these small RNAs are produced, how they patrol the genome, and how they induce heterochromatin. Our group studies how short RNAs lock transposable elements into heterochromatin using the tiny-hairy protozoan Tetrahymena as a model. Moreover, Tetrahymena is able to eliminate heterochromatinized transposable elements from the genome. We are trying to understand how this special ability has been evolved.
Keywords: Small RNA, RNAi, heterochromatin, transposon, Tetrahymena.
Main publications :
Kataoka, K., Noto, T., and Mochizuki, K. (2016) Phosphorylation of an HP1-like protein is a prerequisite for heterochromatin body formation in Tetrahymena DNA elimination. PNAS 113, 9027-32. PMID: 27466409.
Kataoka, K., and Mochizuki, K. (2015) Phosphorylation of an HP1-like protein regulates RNA-bridged heterochromatin body assembly for DNA elimination. Dev Cell 35, 775-788. PMID: 26688337.
Noto, T., Kataoka, K., Suhren, J. H., Hayashi, A., Woolcock, K. J., Gorovsky, M. A. and Mochizuki, K. (2015) Small RNA-mediated genome-wide trans-recognition network in Tetrahymena DNA elimination. Mol Cell 59, 229-242. PMID: 26095658.
Woehrer, S. L, Aronica, L., Suhren, J. H., Busch, C. J., Noto, T and Mochizuki, K. (2015) A Tetrahymena Hsp90 co-chaperone promotes siRNA loading by ATP-dependent and ATP-independent mechanisms. EMBO Journal 34, 559-577. PMID: 25588944.
Vogt, A., and Mochizuki, K. (2013) A domesticated piggyBac transposase interacts with heterochromatin and catalyzes DNA elimination in Tetrahymena. PLoS Genet 8, e1002732. PMID: 24348275.
Schoeberl, U. E., Kurth, H. M., Noto, T. and Mochizuki, K. (2012) Biased transcription and selective degradation of small RNAs shape the pattern of DNA elimination in Tetrahymena. Genes Dev 26, 1729-1742. PMID: 22855833.
Noto, T., Kurth H.M., Kataoka, K. Aronica, L., Desouza, L.V., Siu, K.W., Pearlman, R.E., Gorovsky, M.A., and Mochizuki, K. (2010) The Tetrahymena Argonaute-binding protein Giw1p directs a mature Argonaute-siRNA complex to the nucleus. Cell 140, 692-703. PMID: 20211138.
Aronica, L., Bednenko, J., Noto, T., Desouza, L.V., Siu, K.W., Loidl, J., Pearlman, R.E., Gorovsky, M.A., and Mochizuki, K. (2008) Study of an RNA helicase implicates small RNA-noncoding RNA interactions in programmed DNA elimination in Tetrahymena. Genes Dev 22, 2228-2241. PMID: 18708581.
Mochizuki, K., and Gorovsky, M. A. (2005) A Dicer-like protein in Tetrahymena has distinct functions in genome rearrangement, chromosome segregation, and meiotic prophase. Genes Dev 19, 77-89. PMID: 15598983.
Mochizuki, K., Fine, N. A., Fujisawa, T., and Gorovsky, M. A. (2002) Analysis of a piwi-related gene implicates small RNAs in genome rearrangement in Tetrahymena. Cell 110, 689-699. PMID: 12297043.
