The role of DNA base modifications
<p>One day in 2006, while a postdoc in the Rockefeller University laboratory of Nathaniel Heintz, I had an unexpected eye-opener. Heintz showed me some electron microscopy images of Purkinje neuron nuclei in the murine cerebellum. They stunned me—the heterochromatin localization in the nucleus...
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| Format: | Journal article |
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Scientist, Inc.
2017
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| _version_ | 1797059274521706496 |
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| author | Kriaucionis, S |
| author_facet | Kriaucionis, S |
| author_sort | Kriaucionis, S |
| collection | OXFORD |
| description | <p>One day in 2006, while a postdoc in the Rockefeller University laboratory of Nathaniel Heintz, I had an unexpected eye-opener. Heintz showed me some electron microscopy images of Purkinje neuron nuclei in the murine cerebellum. They stunned me—the heterochromatin localization in the nucleus was different from anything I’d ever seen before. Rather than the dispersed, irregular patches with enrichment near nuclear membrane typical of many cells, nearly all the heterochromatin was in the center of the nucleus, adhered to the single large nucleolus. Not only did heterochromatin organization look different, the volume of it in Purkinje neurons seemed much lower, too. Because links between DNA methylation and heterochromatin proteins were suggested in the literature, we thought that DNA methylation might be depleted in Purkinje neurons.</p> <br/> <p>After nearly a year of work, I was able to isolate enough Purkinje nuclei to start quantifying DNA methylation using thin-layer chromatography. This technique usually yields a single spot per each base in the DNA neighboring G. Normally, five intense spots representing the bases A, G, T, C, and methylated C (known as 5-methylcytosine, or 5mC) migrate to expected locations. In our experiments with Purkinje neuron DNA, however, we consistently noticed the presence of a sixth spot that had not been previously described. Could the spot represent a novel DNA base variant, which had gone unrecognized due to the low abundance of Purkinje neurons in the brain? (In the cerebellum, they constitute just 0.3 percent of all cell types.) After several long months of research, we identified the suspect: a cytosine base that had not only a methyl group added, but also a hydroxyl. We identified this new mark as 5-hydroxymethylcytosine (5hmC).</p> |
| first_indexed | 2024-03-06T20:01:52Z |
| format | Journal article |
| id | oxford-uuid:27942732-571a-4ece-9d47-504ffb68e04e |
| institution | University of Oxford |
| last_indexed | 2024-03-06T20:01:52Z |
| publishDate | 2017 |
| publisher | Scientist, Inc. |
| record_format | dspace |
| spelling | oxford-uuid:27942732-571a-4ece-9d47-504ffb68e04e2022-03-26T12:07:47ZThe role of DNA base modificationsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:27942732-571a-4ece-9d47-504ffb68e04eSymplectic Elements at OxfordScientist, Inc.2017Kriaucionis, S<p>One day in 2006, while a postdoc in the Rockefeller University laboratory of Nathaniel Heintz, I had an unexpected eye-opener. Heintz showed me some electron microscopy images of Purkinje neuron nuclei in the murine cerebellum. They stunned me—the heterochromatin localization in the nucleus was different from anything I’d ever seen before. Rather than the dispersed, irregular patches with enrichment near nuclear membrane typical of many cells, nearly all the heterochromatin was in the center of the nucleus, adhered to the single large nucleolus. Not only did heterochromatin organization look different, the volume of it in Purkinje neurons seemed much lower, too. Because links between DNA methylation and heterochromatin proteins were suggested in the literature, we thought that DNA methylation might be depleted in Purkinje neurons.</p> <br/> <p>After nearly a year of work, I was able to isolate enough Purkinje nuclei to start quantifying DNA methylation using thin-layer chromatography. This technique usually yields a single spot per each base in the DNA neighboring G. Normally, five intense spots representing the bases A, G, T, C, and methylated C (known as 5-methylcytosine, or 5mC) migrate to expected locations. In our experiments with Purkinje neuron DNA, however, we consistently noticed the presence of a sixth spot that had not been previously described. Could the spot represent a novel DNA base variant, which had gone unrecognized due to the low abundance of Purkinje neurons in the brain? (In the cerebellum, they constitute just 0.3 percent of all cell types.) After several long months of research, we identified the suspect: a cytosine base that had not only a methyl group added, but also a hydroxyl. We identified this new mark as 5-hydroxymethylcytosine (5hmC).</p> |
| spellingShingle | Kriaucionis, S The role of DNA base modifications |
| title | The role of DNA base modifications |
| title_full | The role of DNA base modifications |
| title_fullStr | The role of DNA base modifications |
| title_full_unstemmed | The role of DNA base modifications |
| title_short | The role of DNA base modifications |
| title_sort | role of dna base modifications |
| work_keys_str_mv | AT kriaucioniss theroleofdnabasemodifications AT kriaucioniss roleofdnabasemodifications |