CHROMOMERIC ORGANIZATION OF INTERPHASE CHROMOSOMES IN DROSOPHILA MELANOGASTER
I.F. Zhimulev, E.S. Belyaeva, T.Yu. Zykova (Vatolina), V.F. Semeshin., S.A. Demakov,
O.V. Demakova, F.P. Goncharov, G.V. Pokholkova, V.A. Khoroshko, L.V. Boldyreva, E.B. Kokoza
Institute of Molecular and Cellular Biology SB RAS, Novosibirsk;
e-mail: zhimulev@mcb.nsc.ru
As a result of treatment of bioinformatic data on the genome localization of structural proteins, histone modifications, DNase-hypersensitive regions, replication origins (taken from
modENCODE) and their cytological localization to polytene chromosome structures, it is shown here that two types of interphase chromosomes - polytene chromosomes from salivary
glands and from mitotically dividing cells cultures - demonstrate identical pictures of interband/band, i.e. the same localization and length on physical map and the same sets of proteins.
In the interbands of both types the proteins are situated which control initiation of transcription (RNA-polymerase II, transcription factors), replication (ORC2) as well as proteins
modifying nucleosome structure (WDS, NURF) and proteins of insulators (BEAF). In the interbands the nucleosome density and H1 histone concentration are depleted; localization of
DNase-hypersensitive regions is strictly correspond to interbands. So, we conclude that both polytene and cell line interphase chromosomes are arranged according to general principle
and polytene chromosomes represent precise model of interphase chromosomes. The interbands play most impotent role in processes of transcription and replication initiation.
The interbands of interphase chromosomes are the sites of 5'partsof genes, the 3' gene ends being located in neighbor bands. The constance of decondensation of interbands result in
conclusion that the 'interbands' genes are constantly active, i.e. they contain the 'house-keeping' genes. The big late replicating bands contain genes which do not have direct contact to
the adjoining interbands are usually polygenic and contain tissue-specific genes.
Key words: polytene chromosomes, interband/band, interphase chromosomes, Drosophila melanogaster, house-keeping genes
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