The faint band/interband region 28C2 to 28C4-5(−) of the Drosophila melanogaster salivary gland polytene chromosomes is rich in transcripts

1991 ◽  
Vol 226-226 (1-2) ◽  
pp. 81-87 ◽  
Author(s):  
Thomas B. Friedman ◽  
Kelly N. Owens ◽  
Jean B. Burnett ◽  
Anja O. Saura ◽  
Lori L. Wallrath
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Polytene Chromosomes ◽  
Faint Band ◽  
Interband Region

p75, a polypeptide component of karyoskeletal protein-enriched fractions associated with transcriptionally active loci of Drosophila melanogaster polytene chromosomes

1988 ◽  
Vol 8 (5) ◽  
pp. 1877-1886
Author(s):  
B M Benton ◽  
S Berrios ◽  
P A Fisher
Keyword(s):  
Tissue Culture ◽  
Drosophila Melanogaster ◽  
Transcriptional Regulation ◽  
Salivary Gland ◽  
Indirect Immunofluorescence ◽  
Polytene Chromosomes ◽  
Nuclear Interior ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Larval Salivary Gland

A 75-kilodalton polypeptide has been identified which copurifies with karyoskeletal protein-enriched fractions prepared from Drosophila melanogaster embryos. Results of indirect immunofluorescence experiments suggest that this protein, here designated p75, is primarily associated with puffed regions of larval salivary gland polytene chromosomes. In nonpolytenized Schneider 2 tissue culture cells, p75 appeared to be localized throughout the nuclear interior during interphase. In mitotic cells, p75 was redistributed diffusely. A possible role for karyoskeletal elements in transcriptional regulation is discussed.

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.

The genetic analysis of puffing in polytene chromosomes of Drosophila

1970 ◽  
Vol 176 (1044) ◽  
pp. 319-327 ◽  
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Genetic Analysis ◽  
Structural Gene ◽  
Chromosome Aberrations ◽  
Polytene Chromosomes ◽  
Drosophila Simulans ◽  
Salivary Gland Chromosome ◽  
Observed Behaviour

The characteristics of several mutants of Drosophila melanogaster and Drosophila simulans lacking particular salivary gland chromosome puffs are described. On the basis of their observed behaviour in heterozygotes these puff mutants can be classified into puff structural gene and puff regulating gene mutants. Other types of mutation affecting the larval and prepupal puffing cycle include lethals, mutants controlling puff size, and chromosome aberrations which divide a puff into two separate puffs.

scholarly journals p75, a polypeptide component of karyoskeletal protein-enriched fractions associated with transcriptionally active loci of Drosophila melanogaster polytene chromosomes.

1988 ◽  
Vol 8 (5) ◽  
pp. 1877-1886 ◽  
Author(s):  
B M Benton ◽  
S Berrios ◽  
P A Fisher
Keyword(s):  
Tissue Culture ◽  
Drosophila Melanogaster ◽  
Transcriptional Regulation ◽  
Salivary Gland ◽  
Indirect Immunofluorescence ◽  
Polytene Chromosomes ◽  
Nuclear Interior ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Larval Salivary Gland

A 75-kilodalton polypeptide has been identified which copurifies with karyoskeletal protein-enriched fractions prepared from Drosophila melanogaster embryos. Results of indirect immunofluorescence experiments suggest that this protein, here designated p75, is primarily associated with puffed regions of larval salivary gland polytene chromosomes. In nonpolytenized Schneider 2 tissue culture cells, p75 appeared to be localized throughout the nuclear interior during interphase. In mitotic cells, p75 was redistributed diffusely. A possible role for karyoskeletal elements in transcriptional regulation is discussed.

scholarly journals Toroidal bands in polytene chromosomes of Drosophila

1983 ◽  
Vol 64 (1) ◽  
pp. 255-264
Author(s):  
V. Sorsa
Keyword(s):  
Electron Microscopy ◽  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Thin Section ◽  
Polytene Chromosomes ◽  
Thin Sections ◽  
Sister Chromatids ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

Results obtained from the thin-section electron microscopy of salivary gland chromosomes of Drosophila melanogaster mainly support the concept of cable-like organization of polytene chromosomes, with disk-like bands composed of parallel bundles of homologous chromomeres. Outward orientation of loop fibres may generally cause a toroidal bending in the chromomere bundles. Both longitudinal and transverse sections of polytene chromosomes indicate that the bands may contain toroidal subunits. Torus-shaped bands were only found in thin sections of the most distal and most proximal regions, as well as in certain heavy bands at the late-replicating regions of polytenized interphase chromosomes. This suggests that an incomplete duplication of chromomeres may be a reason for torus formation, by preventing the separation of sister chromatids at the earliest phases of the polytenization process. The appearance of more numerous, but smaller, subunits in thin-sectioned faint bands is interpreted as a consequence of more complete segregation of sister chromatids in those bands during polytenization.

LARVAL AGE AND THE PATTERN OF DNA SYNTHESIS IN POLYTENE CHROMOSOMES

1968 ◽  
Vol 10 (1) ◽  
pp. 82-90 ◽  
Author(s):  
David Nash ◽  
John Bell
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Dna Synthesis ◽  
Polytene Chromosomes ◽  
Larval Life ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Puparium Formation ◽  
Chromosome Ii ◽  
Replicative Cycle

It has been shown, by autoradiography using H3-thymidine, that the frequency of salivary gland cells where DNA synthesis covers the entire length of a specific polytene chromosomal segment (Chromosome II, 56F-60A, Drosophila melanogaster) drops off some time during the last day of larval life. The frequency of highly discontinuous DNA synthesis over the same region remains at about the same level until a stage closer to puparium formation, when all DNA synthesis stops.If a cycle of DNA synthesis, once initiated, goes to completion, then this finding indicates that the patterns of spatially continuous synthesis tend to occur early in the replicative cycle and that the terminal phases of the cycle involve highly discontinuous patterns of synthesis.

scholarly journals CHROMOSOMAL BASIS OF DOSAGE COMPENSATION IN DROSOPHILA

1970 ◽  
Vol 47 (1) ◽  
pp. 18-33 ◽  
Author(s):  
S. C. Lakhotia ◽  
A. S. Mukherjee
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Polytene Chromosomes ◽  
Similar Frequency ◽  
Male And Female ◽  
Model Sequence

Thymidine-3H labeling patterns on the X (section 1 A to 12 E of Bridges' map) and 2 R (section 56 F to 60 F of Bridges' map) segments in the salivary gland chromosomes of Drosophila melanogaster have been analyzed in male and female separately. The observed patterns fit, with a few exceptions, in a continuous to discontinuous labeling sequence. In nuclei with similar labeling patterns on the 2R segment in both sexes, the number of labeled sites on the X in male is always less than in female X's. The labeling frequency of the different sites on the male X is considerably lower than those on the female X's, while the sites on the 2R segment have very similar frequency in the two sexes. The rate of thymidine-3H incorporation (as judged by visual grain counting) is relatively higher in male X than in female X's. It is concluded that the model sequence of replication in polytene chromosomes follows a continuous to discontinuous labeling sequence, and that the single X in male completes its replication earlier than either the autosomes in male or the X's in female. This asynchronous and faster rate of replication by the polytene X-chromosome in male substantiates the hypothesis of hyperactivity of the single X in male as the chromosomal basis of dosage compensation in Drosophila.

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