Progress in Molecular and Subcellular Biology : Centromere Structure and Evolution

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The centromere is a chromosomal region that enables the accurate segregation of chromosomes during mitosis and meiosis. It holds sister chromatids together, and through its centromere DNA–protein complex known as the kinetochore binds spindle microtubules to bring about accurate chromosome movements. Despite this conserved function, centromeres exhibit dramatic difference in structure, size, and complexity. Extensive studies on centromeric DNA revealed its rapid evolution resulting often in significant difference even among closely related species. Such a plasticity of centromeric DNA could be explained by epigenetic control of centromere function, which does not depend absolutely on primary DNA sequence. According to epigenetic centromere concept, which is thoroughly discussed by Tanya Panchenko and Ben Black in Chap. 1 of this book, centromere activation or inactivation might be caused by modifications of chromatin. Such acquired chromatin epigenetic modifications are then inherited from one cell division to the next. Concerning centromere-specific chromatin modification, it is now evident that all centromeres contain a centromere specific histone H3 variant, CenH3, which replaces histone H3 in centromeric nucleosomes and provides a structural basis that epigenetically defines centromere and differentiates it from the surrounding chromatin. Recent insights into the CenH3 presented in this chapter add important mechanistic understanding of how centromere identity is initially established and subsequently maintained in every cell cycle. To explain contradiction between rapid evolution of centromeric DNA and centromeric histones on one site and conservation of centromere function on the other one, a model termed “centromere drive” has been proposed by Steven Henikoff and Harmit Malik in 2002. According to this model, asymmetry in female meiosis a cts as a driving force in centromere evolution by inducing a constant genetic conflict between two essential genetic elements: centromeric satellite DNA and centromeric histones or other satellite-binding proteins. Such a conflict is responsible for rapid centromere evolution. In Chap. 2 of this book, Harmit Malik summarizes the evidence in favor of the centromere-drive model and its implications for centromere evolution.

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Judul Seri

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No. Panggil

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Penerbit

Pasuruan : ., 2009

Deskripsi Fisik

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Bahasa

English

ISBN/ISSN

978-3-642-00181-9

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NONE

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Tipe Media

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