Polytene Chromosomes - A Portrait of Functional Organization of the Drosophila Genome.

Polytene Chromosomes - A Portrait of Functional Organization of the Drosophila Genome.
Curr Genomics. 2018 Apr;19(3):179-191
Authors: Zykova TY, Levitsky VG, Belyaeva ES, Zhimulev IF
Abstract
This mini-review is devoted to the problem genetic meaning of main polytene chromosome structures - bands and interbands. Generally, densely packed chromatin forms black bands, moderately condensed regions form grey loose bands, whereas decondensed regions of the genome appear as interbands. Recent progress in the annotation of the Drosophila genome and epigenome has made it possible to compare the banding pattern and the structural organization of genes, as well as their activity. This was greatly aided by our ability to establish the borders of bands and interbands on the physical map, which allowed to perform comprehensive side-by-side comparisons of cytology, genetic and epigenetic maps and to uncover the association between the morphological structures and the functional domains of the genome. These studies largely conclude that interbands 5'-ends of housekeeping genes that are active across all cell types. Interbands are enriched with proteins involved in transcription and nucleosome remodeling, as well as with active histone modifications. Notably, most of the replication origins map to interband regions. As for grey loose bands adjacent to interbands, they typically host the bodies of house-keeping genes. Thus, the bipartite structure co...

Source: Current Genomics - April 3, 2018 Category: Genetics & Stem Cells Tags: Curr Genomics Source Type: research