Tethering of CHROMATOR and dCTCF proteins results in decompaction of condensed bands in the Drosophila melanogaster polytene chromosomes but does not affect their transcription and replication timing

Although heterochromatin makes up 40% of the Drosophila melanogaster genome, its organization remains little explored, especially in polytene chromosomes, as it is virtually not represented in them due to underreplication. Two all-new approaches were used in this work: (i) with the use of a newly synthesized Drosophila line that carries three mutations, Rif11, SuURESand Su(var)3-906, suppressing the underreplication of heterochromatic regions, we obtained their fullest representation in polytene chromosomes and described their structure; (ii) 20 DNA fragments with known positions on the physical map as well as molecular genetic features of the genome (gene density, histone marks, heterochromatin proteins, origin recognition complex proteins, replication timing sites and satellite DNAs) were mapped in the newly polytenized heterochromatin using FISH and bioinformatics data. The borders of the heterochromatic regions and variations in their positions on arm 3L have been determined for the first time. The newly polytenized heterochromatic material exhibits two main types of morphology: a banding pattern (locations of genes and short satellites) and reticular chromatin (locations of large blocks of satellite DNA). The locations of the banding and reticular polytene heterochromatin was determined on the physical map.

Download Full-text

Chromosomal Distribution of Transposable Elements in Drosophila melanogaster Test of the Ectopic Recombination Model for Maintenance of Insertion Site Number

Genetics ◽

10.1093/genetics/144.1.197 ◽

1996 ◽

Vol 144 (1) ◽

pp. 197-204

Author(s):

Christine Hoogland ◽

Christian Biémont

Keyword(s):

Drosophila Melanogaster ◽

Transposable Elements ◽

Dna Content ◽

Recombination Rate ◽

Alternative Hypothesis ◽

Insertion Site ◽

Polytene Chromosomes ◽

Negative Relationship ◽

Site Occupancy ◽

Site Number

Abstract Data of insertion site localization and site occupancy frequency of P, hobo, I, copia, mdg1, mdg3, 412, 297, and roo transposable elements (TEs) on the polytene chromosomes of Drosophila melanogaster were extracted from the literature. We show that TE insertion site number per chromosomal division was significantly correlated with the amount of DNA. The insertion site number weighted by DNA content was not correlated with recombination rate for all TEs except hobo, for which a positive correlation was detected. No global tendency emerged in the relationship between TE site occupancy frequency, weighted by DNA content, and recombination rate; a strong negative correlation was, however, found for the 3L arm. A possible dominant deleterious effect of chromosomal rearrangements due to recombination between TE insertions is thus not the main factor explaining the dynamics of TEs, since this hypothesis implies a negative relationship between recombination rate and both TE insertion site number and site occupancy frequency. The alternative hypothesis of selection against deleterious effects of insertional mutations is discussed.

Download Full-text

Microdissection and cloning of DNA from a specific region of Drosophila melanogaster polytene chromosomes

Chromosoma ◽

10.1007/bf00286105 ◽

1981 ◽

Vol 82 (2) ◽

pp. 205-216 ◽

Cited By ~ 214

Author(s):

F. Scalenghe ◽

E. Turco ◽

J. E. Edström ◽

V. Pirrotta ◽

M. Melli

Keyword(s):

Drosophila Melanogaster ◽

Polytene Chromosomes ◽

Specific Region

Download Full-text

A cDNA from Drosophila melanogaster encodes a lamin C-like intermediate filament protein

Journal of Cell Science ◽

10.1242/jcs.104.4.1263 ◽

1993 ◽

Vol 104 (4) ◽

pp. 1263-1272 ◽

Cited By ~ 4

Author(s):

C.A. Bossie ◽

M.M. Sanders

Keyword(s):

Drosophila Melanogaster ◽

Intermediate Filament ◽

Blot Analysis ◽

Polytene Chromosomes ◽

Intermediate Filament Protein ◽

Chromosome 2 ◽

Cross Hybridization ◽

Intermediate Filament Proteins ◽

Nuclear Lamins ◽

Filament Protein

A novel intermediate filament cDNA, pG-IF, has been isolated from a Drosophila melanogaster embryonic expression library screened with a polyclonal antiserum produced against a 46 kDa cytoskeletal protein isolated from Kc cells. This 46 kDa protein is known to be immunologically related to vertebrate intermediate filament proteins. The screen resulted in the isolation of four different cDNA groups. Of these, one has been identified as the previously characterized Drosophila nuclear lamin cDNA, Dm0, and a second, pG-IF, demonstrates homology to Dm0 by cross hybridization on Southern blots. DNA sequence analysis reveals that pG-IF encodes a newly identified intermediate filament protein in Drosophila. Its nucleotide sequence is highly homologous to nuclear lamins with lower homology to cytoplasmic intermediate filament proteins. pG-IF predicts a protein of 621 amino acids with a predicted molecular mass of 69,855 daltons. In vitro transcription and translation of pG-IF yielded a protein with a SDS-PAGE estimated molecular weight of approximately 70 kDa. It contains sequence principles characteristic of class V intermediate filament proteins. Its near neutral pI (6.83) and the lack of a terminal CaaX motif suggests that it may represent a lamin C subtype in Drosophila. In situ hybridization to polytene chromosomes detects one band of hybridization on the right arm of chromosome 2 at or near 51A. This in conjunction with Southern blot analysis of various genomic digests suggests one or more closely placed genes while Northern blot analysis detects two messages in Kc cells.

Download Full-text

Association of a protease with polytene chromosomes of Drosophila melanogaster.

The Journal of Cell Biology ◽

10.1083/jcb.87.2.415 ◽

1980 ◽

Vol 87 (2) ◽

pp. 415-419 ◽

Cited By ~ 5

Author(s):

J Cavagnaro ◽

D A Pierce ◽

J C Lucchesi ◽

C B Chae

Keyword(s):

Acetic Acid ◽

Drosophila Melanogaster ◽

Heat Shock ◽

Protease Inhibitors ◽

Polytene Chromosomes ◽

Fixation Procedure ◽

Apparent Effect ◽

Chloromethyl Ketone ◽

Diisopropyl Fluorophosphate ◽

Uniform Labeling

Incubation of Drosophila salivary glands with radioactive diisopropyl fluorophosphate results in the uniform labeling of polytene chromosomes. Extensive labeling is seen only when chromosome squashes are prepared by a formaldehyde fixation procedure and not by standard acetic acid techniques. The labeling is inhibited in the presence of tosylphenylalanine chloromethyl ketone and phenylmethane sulfonylfluoride but not by tosyllysine chloromethyl ketone, suggesting that a chymotrypsin-like serine protease is associated with the chromosomes. Protease inhibitors show no apparent effect on heat-shock specific puffing.

Download Full-text