scholarly journals Locations of chromosomal proteins in polytene chromosomes.

1976 ◽  
Vol 73 (6) ◽  
pp. 2038-2042 ◽  
Author(s):  
C. R. Alfageme ◽  
G. T. Rudkin ◽  
L. H. Cohen
Keyword(s):  
Polytene Chromosomes ◽  
Chromosomal Proteins

Ultrastructure of polytene chromosomes of Drosophila isolated by microdissection

1980 ◽  
Vol 45 (1) ◽  
pp. 15-30
Author(s):  
M.R. Mott ◽  
E.J. Burnett ◽  
R.J. Hill
Keyword(s):  
Electron Microscope ◽  
Polytene Chromosomes ◽  
Ultrastructural Level ◽  
Chromosomal Proteins ◽  
Linear Arrays ◽  
Ribonucleoprotein Particles ◽  
Acid Protein

Drosophila polytene chromosomes prepared by a new micromanipulative procedure, which avoids acid squashing, have been examined at the ultrastructural level in the electron microscope. Puffs at 2B, 68C, 74EF, 75B and 85EF, have been examined in some detail, along with the chromocentre and various interbands. The ultrastructure of these chromosomes, which have never been exposed to acid protein denaturants, compares favourably with that of classical acid-fixed specimens. Ribonucleoprotein particles in puffs are seen to be organized in linear arrays and evidence is adduced for looped transcription units. Particles with characteristic sizes and morphologies are observed near the chromocentre, in puffs and in interbands. In interbands RNP particles and ‘superbead’-like chromatin particles may be distinguished. Drosophila polytene chromosomes isolated by micro-manipulation should prove useful for the localization of native chromosomal proteins at an ultrastructural level.

scholarly journals A cytological approach to the ordering of events in gene activation using the Sgs-4 locus of Drosophila melanogaster.

1984 ◽  
Vol 99 (1) ◽  
pp. 233-238 ◽  
Author(s):  
E K Steiner ◽  
J C Eissenberg ◽  
S C Elgin
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Topoisomerase I ◽  
Gene Activation ◽  
Polytene Chromosomes ◽  
Null Alleles ◽  
Major Salivary Gland ◽  
Wild Type ◽  
Fluorescent Band ◽  
Chromosomal Proteins

The polytene chromosomes of Drosophila strains that differ in the synthesis of the major salivary gland glue protein sgs-4 were examined by indirect immunofluorescence using antisera to several nonhistone chromosomal proteins. The Oregon-R X chromosome, which produces sgs-4 messenger RNA, showed a strong fluorescent band at locus 3C11-12 when stained with anti-RNA polymerase II, whereas the null mutant Berkeley 1 failed to exhibit fluorescence at that locus. The presence of another antigen (Band 2), normally associated with developmentally active loci, was clearly evident at locus 3C11-12 of both transcriptionally competent and null strains, indicating that the association of Band 2 antigen with the chromatin is an event independent of RNA polymerase II binding. Antibodies directed against Drosophila topoisomerase I stained 3C11-12 in the Sgs-4+ (wild-type) strain brightly, but gave significantly less staining in the null strain. This indicates that the high concentrations of topoisomerase I seen at active loci are closely associated with the transcriptional event. In some of these analyses, we have made use of flies heterozygous for the wild-type and null alleles in order to make internally controlled comparisons. The results suggest that this type of analysis will enable conclusions to be drawn concerning the interdependence and order of action of chromosomal proteins involved in developmental gene activation.

Immunolocalization of chromosomal proteins on polytene chromosomes of

Micron (1969) ◽  
1982 ◽  
Vol 13 (3) ◽  
pp. 301-302
Author(s):  
Margaret R. Mott ◽  
R.J. Hill ◽  
E.J. Burnett
Keyword(s):  
Polytene Chromosomes ◽  
Chromosomal Proteins

Distribution Patterns of Nonhistone Chromosomal Proteins on Polytene Chromosomes: Functional Correlations

1988 ◽  
pp. 145-156 ◽  
Author(s):  
S. C. R. Elgin ◽  
S. A. Amero ◽  
J. C. Eissenberg ◽  
G. Fleischmann ◽  
D. S. Gilmour ◽  
...  
Keyword(s):  
Polytene Chromosomes ◽  
Distribution Patterns ◽  
Chromosomal Proteins
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