Publication Date:
1983-04-29
Description:
Three-dimensional reconstruction of an asymmetric biological ultrastructure has been achieved by tomographic analysis of electron micrographs of sections tilted on a goniometer specimen stage. Aligned micrographs could be displayed as red-green three-dimensional movies. The techniques have been applied to portions of in situ transcription units of a Balbiani ring in the polytene chromosomes of the midge Chironomus tentans. Current data suggest a DNA compaction of about 8 to 1 in a transcription unit. Nascent ribonucleoprotein granules display an imperfect sixfold helical arrangement around the chromatin axis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Olins, D E -- Olins, A L -- Levy, H A -- Durfee, R C -- Margle, S M -- Tinnel, E P -- Dover, S D -- GM-19334/GM/NIGMS NIH HHS/ -- GM-29429/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1983 Apr 29;220(4596):498-500.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6836293" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Chironomidae/genetics/ultrastructure
;
Chromatin/ultrastructure
;
DNA/metabolism
;
Microscopy, Electron/*methods
;
Ribonucleoproteins/metabolism
;
Tomography/*methods
;
*Transcription, Genetic
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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