FIND ARTICLE

Volume: 
Issue: 
2
Date of issue: 

Neocentromeres structures are fully active in the process of separation of chromatids and their targeting towards the poles of the mitotic spindle during mitosis and meiosis . Centromeric chromatin nucleosomes containing protein CENP -A and its homologues , which are variants of histone H3 and determining the identity of the centromere / neocentromeru . Neocentromeres arise in distant zones niecentromerowych chromosomes and therefore contain different centromeric DNA . The creation of the centromere may be a response to inactivation of endogenous centromere . Neocentromeres are usually formed due to rearrangement of chromosomes acentrycznych their fragments , so that the fragment can be moved properly to the spindle poles . Until 2004, the human describes 70 examples of the occurrence of neocentromerów , resulting from chromosomal rearrangements . Particularly susceptible to the formation of chromosome arms are 3q , 13q , and 15q . The creation of functional neocentromerów can be induced in vitro and minichromosomach human mammalian artificial chromosomes. Neocentromeres form after introduction of the cells in culture in vitro by transfection or microinjection of the centromeric DNA. In plants neocentromeres true , i.e. the protein-containing CENH3 ( CENP -A homolog ), and other centromere protein and kinetochores , formed by the rearrangement of chromosomes. The name " neocentromeres " suitable unduly large blocks heterochromatynowym called knobami containing DNA repeats with a length of 350 bp and 180 bp . Knoby bind to microtubules and rapidly move toward the poles during anaphase of meiosis II division . Knoby not contain or CENH3 , or any centromeric proteins . The nuclei endopoliploidalnych , without the ability to mitotic divisions , multiplication of centromeric DNA is not accompanied by a proportional increase in the level of CENH3 . Human neocentromeres euchromatynowych formed in lanes contain , as endogenous chromosome 8 centromere in rice , the sequences unique. Unlike typical neocentromeres centromeres both , as well as the centromeric regions can occur in rice transcription process .

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The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

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Katedra i Zakład Histologii i Embriologii Uniwersytetu Medycznego w Poznaniu, ul. Święcickiego 6, 60-781 Poznań, tel. +48 61 8546453, fax. +48 61 8546440, email: mnowicki@ump.edu.pl

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