ABSTRACT
The search for correlation between structural organization of particular chromosome regions and their functions is among key directions of molecular cytogenetics. In this study, we used polytene chromosomes of Drosophila melanogaster as a convenient model for examining transcriptional activity of chromomeres (bands) and interchromomeres (interbands) in eukaryotic interphase chromosomes. Using cloning of the interband DNA sequences and determination of the molecular limits for some interbands, we analyzed the transcriptional activity of these regions and compared the band and interband transcriptional activity in polytene chromosomes. Our results showed the absence of correlation between the decompacted state of the interbands examined and the levels of transcription observed in these regions.
Subject(s)
Chromatin/metabolism , Polytene Chromosomes/metabolism , Transcription, Genetic/physiology , Animals , Chromatin/genetics , Drosophila melanogaster , Polytene Chromosomes/geneticsABSTRACT
The functional organization of particular chromosome regions is tightly associated with their function in eukaryotic cells. Details of this association are among the most topical problems of modem genetics. The paper characterizes the results of recent research of the specifics of the genetic organization and chromatin decondensation in interbands of Drosophila polytene chromosomes. Data on functional heterogeneity of interbands are considered. Experimental findings point to a lack of correlation between the decondensed chromatin state and the observed transcription level in particular interbands. The DNA sequences responsible for the interband formation are principally identifiable via site-specific homologous FRT/FLP recombination between two P transposons contained in chromosomes. The results allow a search for particular protein factors that are involved in the decondensed state of interbands and structural and functional differentiation of polytene chromosomes.
