Physical structure of gene-sized chromatin from the protozoan Oxytricha
Oxytricha nova is a hypotrichous ciliate containing a transcriptionally active macronucleus and a transcriptionally inactive micronucleus. Two-dimensional gel electrophores is shows that macronuclei contain a normal complement of inner histones. However, despite extensive efforts, no classical H1-li...
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Published in | Nucleic acids research Vol. 12; no. 7; pp. 3201 - 3217 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Oxford University Press
11.04.1984
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Subjects | |
Online Access | Get full text |
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Summary: | Oxytricha nova is a hypotrichous ciliate containing a transcriptionally active macronucleus and a transcriptionally inactive micronucleus. Two-dimensional gel electrophores is shows that macronuclei contain a normal complement of inner histones. However, despite extensive efforts, no classical H1-like protein has been detected. Micrococcal nuclease digestion indicates a nucleosome repeat length of approximately 220 bp for macronuclear chromatin. Thermal denaturation profiles of macronuclear chromatin in 0.2 mM EDTA display four transitions at about 46, 57, 64, and 79°C. The lowest of these shifts to higher temperature as the ionic strength is raised to 3-5 mM Na phosohate. These results are consistent with the absence of H1 and a nucleosome repeat of 220–230 bp. Circular dichroism (CD) results aqree with these findings. By contrast, micronuclear chromatin displays a much smaller premelt and a more suppressed DNA CD signal at 285 nm, consistent with a micronuclear chromatin repeat of 165–185 bp as determined by micrococcal nuclease digestion. |
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Bibliography: | ArticleID:12.7.3201 Research sponsored by the Office of Health and Environmental Research, U.S. Department of Energy, under contract W-7405-eng-26 with Union Carbide Corporation ark:/67375/HXZ-D8KFKF15-9 istex:162ACDFCD85A4CC32D342B11A755FFC30942DE38 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0305-1048 1362-4962 |
DOI: | 10.1093/nar/12.7.3201 |