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Updated: Aug 8, 2026
10:28
Repressing Gene Transcription by Redirecting Cellular Machinery with Chemical Epigenetic Modifiers
Published on: September 20, 2018
Chromosomal subunits in active genes have an altered conformation
Science (New York, N.Y.)
|September 3, 1976
Summary
Active genes in chick red blood cells are preferentially digested by deoxyribonuclease I, indicating their DNA is more accessible. This suggests active genes have a specific histone-DNA conformation making them sensitive to enzymatic digestion.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Gene activity is regulated by chromatin structure.
- Differential DNA accessibility in nuclei suggests varying gene states.
Purpose of the Study:
- To investigate the differential susceptibility of active genes to nuclease digestion.
- To elucidate the role of chromatin conformation in DNA accessibility.
Main Methods:
- Nuclei isolated from chick red blood cells, fibroblasts, and brain were subjected to deoxyribonuclease I digestion.
- Staphylococcal nuclease digestion was performed on red cell nuclei.
- Further deoxyribonuclease I digestion was applied to staphylococcal nuclease-generated monomers.
Main Results:
- Deoxyribonuclease I preferentially digested globin DNA sequences in red blood cell nuclei, but not in other cell types.
- Nontranscribed ovalbumin sequences remained intact after deoxyribonuclease I digestion.
- Staphylococcal nuclease did not preferentially digest active globin genes, but subsequent deoxyribonuclease I digestion of resulting monomers did.
Conclusions:
- Active genes are preferentially digested by deoxyribonuclease I, suggesting increased DNA accessibility.
- This heightened sensitivity is likely due to a specific histone-DNA subunit conformation in active genes.
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