Results of the characterization of a soluble chromatin fraction that is released by brief digestion with micrococcal nuclease are described. Both transcriptionally active sequences and newly replicated sequences are highly enriched in this rapidly released, soluble (RRS) chromatin. RRS fractionation permits 7 to 20 fold enrichments of transscriptionally active sequences and 15 fold enrichments of newly replicated DNA (i.e. compared to the insoluble or P fraction). This functionally important chromatin is more accessible or sensitive to nuclease than the bulk of the chromatin. Greater accessibility is probably a natural consequence of a necessity to interact with regulatory molecules, polymerases, or packaging proteins. RRS chromatin is enriched in HMG 1, 2, 14 and 17 and many other non-histone chromosomal proteins (NHCP). RRS chromatin contains a generally basic subset of NHCP, and RRS chromatin mononucleosomes contain a very basic subset of these. RRS chromatin nucleosomes are highly enriched in a protein we have termed HL4. HL4 was isolated; its amino acid composition indicates it is not a breakdown product of histones or common NHCP. HL4 appears to replace H4 in the nucleosome core. A protein with mobility similar to HL4 also appears in chicken erythrocyte (CE) RRS chromatin. RRS chromatin from CE is very similar to mouse myeloma (MM) RRS chromatin in its protein component and enrichment in transcriptionally active sequences, but differs from the MM system in its low yields and faster sedimenting fractions. Histones 3 and 4 of soluble fraction are less acetylated than in bulk chromatin, but the NHCP of the soluble fraction are highly acetylated. RRS contains many unusual nucleosomes which can be separated into distinct classes. The ability to separate these unusual nucleosomes permits a wide range of future experiments. RRS chromatin provides new insights into functionally important NHCP and the fine structure of active genes. / Source: Dissertation Abstracts International, Volume: 42-01, Section: B, page: 0042. / Thesis (Ph.D.)--The Florida State University, 1981.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74394 |
| Contributors | CHAMBERS, SCOTT ALLEN., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 196 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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