TY - JOUR

T1 - Faint gray bands in Drosophila melanogaster polytene chromosomes are formed by coding sequences of housekeeping genes

AU - Demakova, Olga V.

AU - Demakov, Sergey A.

AU - Boldyreva, Lidiya V.

AU - Zykova, Tatyana Yu

AU - Levitsky, Victor G.

AU - Semeshin, Valeriy F.

AU - Pokholkova, Galina V.

AU - Sidorenko, Darya S.

AU - Goncharov, Fedor P.

AU - Belyaeva, Elena S.

AU - Zhimulev, Igor F.

PY - 2020/3/1

Y1 - 2020/3/1

N2 - In Drosophila melanogaster, the chromatin of interphase polytene chromosomes appears as alternating decondensed interbands and dense black or thin gray bands. Recently, we uncovered four principle chromatin states (4НММ model) in the fruit fly, and these were matched to the structures observed in polytene chromosomes. Ruby/malachite chromatin states form black bands containing developmental genes, whereas aquamarine chromatin corresponds to interbands enriched with 5′ regions of ubiquitously expressed genes. Lazurite chromatin supposedly forms faint gray bands and encompasses the bodies of housekeeping genes. In this report, we test this idea using the X chromosome as the model and MSL1 as a protein marker of the lazurite chromatin. Our bioinformatic analysis indicates that in the X chromosome, it is only the lazurite chromatin that is simultaneously enriched for the proteins and histone marks associated with exons, transcription elongation, and dosage compensation. As a result of FISH and EM mapping of a dosage compensation complex subunit, MSL1, we for the first time provide direct evidence that lazurite chromatin forms faint gray bands. Our analysis proves that overall most of housekeeping genes typically span from the interbands (5′ region of the gene) to the gray band (gene body). More rarely, active lazurite chromatin and inactive malachite/ruby chromatin may be found within a common band, where both the housekeeping and the developmental genes reside together.

AB - In Drosophila melanogaster, the chromatin of interphase polytene chromosomes appears as alternating decondensed interbands and dense black or thin gray bands. Recently, we uncovered four principle chromatin states (4НММ model) in the fruit fly, and these were matched to the structures observed in polytene chromosomes. Ruby/malachite chromatin states form black bands containing developmental genes, whereas aquamarine chromatin corresponds to interbands enriched with 5′ regions of ubiquitously expressed genes. Lazurite chromatin supposedly forms faint gray bands and encompasses the bodies of housekeeping genes. In this report, we test this idea using the X chromosome as the model and MSL1 as a protein marker of the lazurite chromatin. Our bioinformatic analysis indicates that in the X chromosome, it is only the lazurite chromatin that is simultaneously enriched for the proteins and histone marks associated with exons, transcription elongation, and dosage compensation. As a result of FISH and EM mapping of a dosage compensation complex subunit, MSL1, we for the first time provide direct evidence that lazurite chromatin forms faint gray bands. Our analysis proves that overall most of housekeeping genes typically span from the interbands (5′ region of the gene) to the gray band (gene body). More rarely, active lazurite chromatin and inactive malachite/ruby chromatin may be found within a common band, where both the housekeeping and the developmental genes reside together.

KW - 4HMM chromatin model

KW - Chromatin types

KW - Drosophila

KW - Housekeeping genes

KW - MSL1

KW - Polytene chromosome bands and interbands

UR - http://www.scopus.com/inward/record.url?scp=85076372283&partnerID=8YFLogxK

U2 - 10.1007/s00412-019-00728-2

DO - 10.1007/s00412-019-00728-2

M3 - Article

C2 - 31820086

AN - SCOPUS:85076372283

VL - 129

SP - 25

EP - 44

JO - Chromosoma

JF - Chromosoma

SN - 0009-5915

IS - 1

ER -