Drosophila D1 overexpression induces ectopic pairing of polytene chromosomes and is deleterious to development

Chromosoma ◽  
2010 ◽  
Vol 119 (3) ◽  
pp. 287-309 ◽  
Author(s):  
Marissa B. Smith ◽  
Karen S. Weiler
Keyword(s):  
Polytene Chromosomes ◽  
Ectopic Pairing

Polytene and mitotic chromosome analysis in Ceratitis capitata (Diptera; Tephritidae)

1986 ◽  
Vol 28 (2) ◽  
pp. 180-188 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
X Chromosome ◽  
Silver Staining ◽  
Mitotic Chromosome ◽  
Ceratitis Capitata ◽  
Fat Body ◽  
Polytene Chromosomes ◽  
Chromosome Analysis ◽  
Mitotic Chromosomes ◽  
Chromosome Separation ◽  
Ectopic Pairing

Polytene chromosomes were found in several larval and pupal tissues of the Medfly, Ceratitis capitata, during a search for chromosomes suitable for detailed cytological analysis. Well-banded highly polytene chromosomes, which could be adequately separated and spread, were found in trichogen cells of the spatulate superior orbital bristles of male pupae. These chromosomes proved suitable for full polytene analysis. Thoracic trichogen cells of both male and female pupae also contain useful polytene chromosomes, although they are considerably thinner and thus more difficult to analyze. Contrasting with those in pupal trichogen cells, the chromosomes in the salivary glands, Malphighian tubules, midgut, hindgut, and fat body of larvae and pupae were difficult to prepare because of high levels of ectopic pairing and chromosome fragmentation. In hindgut preparations partial separation of up to three chromosomes was achieved, but in all other tissues no useful chromosome separation was possible. In trichogen polytene cells, five banded chromosomes and a prominent heterochromatic network associated with a nucleolus are found. The mitotic chromosomes respond to C- and Q-banding and silver staining with considerable variation. This is especially so in the X chromosome, which displays an extensive array of bands following both Q-banding and silver staining. Comparison of Q-banded metaphase and polytene chromosomes demonstrates that the five autosomes are represented by conventional polytene chromosomes, while the sex chromosomes are contained in the heterochromatic net, most of which fluoresces strongly. This suggests that the Q-bands of the mitotic X chromosome are replicated to a greater extent than the nonfluorescent material in polytene cells. This investigation shows C. capitata to have excellent cytological material for both polytene and mitotic analysis.Key words: Ceratitis capitata, Medfly, chromosomes (polytene), banding (chromosome).

XV.—“Ectopic” Pairing and the Distribution of Heterochromatin in the X-Chromosome of Salivary Gland Nuclei of Drosophila melanogaster

1946 ◽  
Vol 62 (2) ◽  
pp. 114-119 ◽  
Author(s):  
B. M. Slizynski
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Nucleic Acid ◽  
X Chromosome ◽  
Polytene Chromosomes ◽  
Ectopic Pairing

The problem to be presented here emerges from the following groups of facts and more or less generally accepted opinions.As heterochromatin we may define those parts of chromosomes which reach maximum nucleic acid charge in mitosis or meiosis in times other than metaphase. In salivary gland chromosomes (which are more conveniently called polytene chromosomes) of Drosophila melanogaster the proximal heterochromatic parts of all chromosomes come together and form a central undifferentiated mass, the chromocentre. Genetically heterochromatin forms the so-called inert regions of the chromosomes.

Cytogenetic analysis of Malpighian tubule and salivary gland polytene chromosomes of Bactrocera oleae (Dacus oleae) (Diptera: Tephritidae)

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1070-1081 ◽  
Author(s):  
Anna Zambetaki ◽  
Kleanthis Kleanthous ◽  
Penelope Mavragani-Tsipidou
Keyword(s):  
Salivary Gland ◽  
Banding Pattern ◽  
Fat Body ◽  
Polytene Chromosomes ◽  
Malpighian Tubule ◽  
Bactrocera Oleae ◽  
Dacus Oleae ◽  
Somatic Tissues ◽  
Ectopic Pairing ◽  
Tandem Duplications

Photomaps of the Malpighian tubule and the salivary gland polytene chromosomes of Bactrocera oleae (Dacus oleae) are presented and compared with those of the fat body. Five polytene chromosomes (10 polytene arms) corresponding to the five autosomes of the mitotic nuclei, as well as a heterochromatic mass corresponding to the sex chromosomes, are observed in the nuclei of the three somatic tissues. The most prominent features of each polytene chromosome, the reverse tandem duplications, as well as the rather unusual ectopic pairing of the telomeric regions of different chromosome arms, are described. The constancy of the banding pattern based on the analysis of the three larval tissues is discussed.Key words: Bactrocera oleae (Dacus oleae), polytene chromosomes, salivary gland, Malpighian tubule, banding pattern.

scholarly journals Evaluation of the mutagenic potential of propoxur and methyl parathion using polytene chromosomes of Anopheles stephensi

2012 ◽  
Vol 4 (1) ◽  
pp. 79-84
Author(s):  
Asha Chaudhry ◽  
Preety Bhinder ◽  
Ram Kumar ◽  
Ravneet Kaur
Keyword(s):  
X Chromosome ◽  
Methyl Parathion ◽  
Anopheles Stephensi ◽  
Polytene Chromosomes ◽  
Mutagenic Potential ◽  
X Chromosomes ◽  
Structural Aberrations ◽  
Ectopic Pairing ◽  
Pesticide Genotoxicity

The mutagenicity of two pesticides, propoxur and methyl parathion was evaluated by using polytene chromosomes of Anopheles stephensi. The results were based on the frequency of various structural aberrations encountered in the polytene chromosomes of the larvae treated with LC20 of propoxur and methyl parathion separately. Propoxur induced a total of 67 aberrations as against 15 in the controls while methyl parathion induced 53 aberrations as against 13 in the controls. These aberrations were dominated by inversions, translocations, deletions, ectopic pairing, asynapses, breaks, fusions and induced puffing. The frequency of propoxur induced aberrations was highest in chromosome 3R followed by 2R, 3L, 2L and X-chromosome. Methyl parathion induced highest number of aberrations in 2R followed by 2L, 3R, 3L and X-chromosomes. This study suggests that larval polytene chromosomes are sensitive indicators of pesticide genotoxicity in which both propoxur and methyl parathion are significantly chromotoxic for the genome of a mosquito taken as an experimental insect.

DNA underreplication in intercalary heterochromatin regions in polytene chromosomes of Drosophila melanogaster correlates with the formation of partial chromosomal aberrations and ectopic pairing

Chromosoma ◽  
2006 ◽  
Vol 115 (5) ◽  
pp. 355-366 ◽  
Author(s):  
Elena S. Belyaeva ◽  
Sergey A. Demakov ◽  
Galina V. Pokholkova ◽  
Artyom A. Alekseyenko ◽  
Tatiana D. Kolesnikova ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosomal Aberrations ◽  
Polytene Chromosomes ◽  
Intercalary Heterochromatin ◽  
Ectopic Pairing

scholarly journals Chromatin Structure and “DNA Sequence View”: The Role of Satellite DNA in Ectopic Pairing of the Drosophila X Polytene Chromosome

2021 ◽  
Vol 22 (16) ◽  
pp. 8713
Author(s):  
Aleksandr V. Zhuravlev ◽  
Gennadii A. Zakharov ◽  
Ekaterina V. Anufrieva ◽  
Anna V. Medvedeva ◽  
Ekaterina A. Nikitina ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Dna Sequences ◽  
Wild Type Strain ◽  
3D Structure ◽  
Polytene Chromosomes ◽  
Wild Type ◽  
Analysis Software ◽  
Drosophila Model ◽  
Ectopic Pairing

Chromatin 3D structure plays a crucial role in regulation of gene activity. Previous studies have envisioned spatial contact formations between chromatin domains with different epigenetic properties, protein compositions and transcription activity. This leaves specific DNA sequences that affect chromosome interactions. The Drosophila melanogaster polytene chromosomes are involved in non-allelic ectopic pairing. The mutant strain agnts3, a Drosophila model for Williams–Beuren syndrome, has an increased frequency of ectopic contacts (FEC) compared to the wild-type strain Canton-S (CS). Ectopic pairing can be mediated by some specific DNA sequences. In this study, using our Homology Segment Analysis software, we estimated the correlation between FEC and frequency of short matching DNA fragments (FMF) for all sections of the X chromosome of Drosophila CS and agnts3 strains. With fragment lengths of 50 nucleotides (nt), CS showed a specific FEC–FMF correlation for 20% of the sections involved in ectopic contacts. The correlation was unspecific in agnts3, which may indicate the alternative epigenetic mechanisms affecting FEC in the mutant strain. Most of the fragments that specifically contributed to FMF were related to 1.688 or 372-bp middle repeats. Thus, middle repetitive DNA may serve as an organizer of ectopic pairing.

Cytotaxonomic differentiation of Wilhelmia equina (Linné, 1747) and Wilhelmia lineata (Meigen, 1804) (Diptera: Simuliidae)

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 589-595 ◽  
Author(s):  
E. Andreas Weber ◽  
Jörg Grunewald
Keyword(s):  
Salivary Gland ◽  
Banding Pattern ◽  
Polytene Chromosomes ◽  
Morphological Characteristics ◽  
Nucleolus Organizer ◽  
Banding Patterns ◽  
Chromosomal Banding ◽  
Chromosome Maps ◽  
Chromosomal Polymorphisms ◽  
Ectopic Pairing

In most cases the larvae of Wilhelmia equina and W. lineata cannot be distinguished by using classical morphological features. The morphological characteristics of the salivary gland polytene chromosomes allow one to differentiate clearly between the two species. Characteristic for W. equina are the extended region between the centromere, Ctr (transformed centromere), and the nucleolus organizer, NO, in IS, the definitive position of RB (ring of Balbiani) and bulge in IIS, and the fan-shaped IIIL telomere. The chromosomes of W. lineata are marked by complex chromosomal polymorphisms, the altered position of RB and bulge on IIS and by a strong ectopic pairing of centromeres. The comparison of banding patterns provides several intraspecific polymorphic inversions and interspecific fixed rearrangements for species diagnosis. Partial chromosome maps were established. The comparison of the chromosomal banding pattern of Wilhelmia with that of the Simulium standard reveals a whole-arm interchange between chromosomes I and II in Wilhelmia identical with that in Metomphalus, Prosimulium vernale, a form of P. mixtum, and Metacnephia.Key words: cytotaxonomy, Simuliidae, Wilhelmia equina, Wilhelmia lineata, larvae.

scholarly journals Molecular Characterization of hobo-Mediated Inversions in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 647-656
Author(s):  
William B Eggleston ◽  
Nac R Rim ◽  
Johng K Lim
Keyword(s):  
X Chromosome ◽  
Polymerase Chain Reaction Amplification ◽  
Polytene Chromosomes ◽  
Chromosomal Inversions ◽  
Hobo Element ◽  
Reaction Amplification ◽  
Notch Locus ◽  
Polymerase Chain

Abstract The structure of chromosomal inversions mediated by hobo transposable elements in the Uc-1 X chromosome was investigated using cytogenetic and molecular methods. Uc-1 contains a phenotypically silent hobo element inserted in an intron of the Notch locus. Cytological screening identified six independent Notch mutations resulting from chromosomal inversions with one breakpoint at cytological position 3C7, the location of Notch. In situ hybridization to salivary gland polytene chromosomes determined that both ends of each inversion contained hobo and Notch sequences. Southern blot analyses showed that both breakpoints in each inversion had hobo-Notch junction fragments indistinguishable in structure from those present in the Uc-1 X chromosome prior to the rearrangements. Polymerase chain reaction amplification of the 12 hobo-Notch junction fragments in the six inversions, followed by DNA sequence analysis, determined that each was identical to one of the two hobo-Notch junctions present in Uc-1. These results are consistent with a model in which hobo-mediated inversions result from homologous pairing and recombination between a pair of hobo elements in reverse orientation.

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