The primary organization of nucleosomal core particles from actively dividing cells of lily

Abstract

Nucleosomal core particles containing different variants of histones H2A and H2B were isolated from actively growing sepals of lily buds (Lilium cundida, L.). The particles had decreased electrophoretic mobility relative to those from other sources. Comparison of the arrangement of histones along DNA in lily nucleosomes with previously obtained data for nucleosomes from yeast and animal cells, either active or repressed with regard to transcription and replication, has revealed no significant differences. The results suggest that the structure of nucleosomal core particles is highly conserved in all eukaryotes, whatever the functional state of the cell and the structure of histones H2A and H2B.

Alterations in Nucleosome Core Structure in Linker Histone-depleted Chromatin

“…Sea urchin sperm, compared with chicken erythrocytes, mouse ascites, and yeast, contains several variants of histone H2B with a considerably extended N-terminal domain containing an additional cluster of lysine and arginine residues (46). Lily, as well as other plants, also contains several variants of histones H2A and H2B that are much longer than those from the other sources studied in this work (28,(47)(48)(49). Our observation that the stretched nucleosome appears in unfolded chromatin from different sources, containing different histone variants with different lengths of N-and C-terminal domains, suggests that this conformational state does not depend on chromatin sources and histone variants.…”

“…1, B and C, respectively). It should be noted that histone H2B from sea urchin sperm and lily bud sepals is much longer in size than that from chicken erythrocytes and migrates slower, above histone H3 in the SDS gel (17,28). Since diagonals corresponding to particular histones in the two-dimensional gel are arranged from left to right in the same order as free histones migrating from top to bottom in the one-dimensional gel (19) (see "Experimental Approach"), the corresponding diagonal of histone H2B in the two-dimensional gels for these two sources is arranged to the very left (Fig.…”

“…These results indicate that the conformation of the nucleosomal core in chromatin depleted of linker histones is similar to that in yeast and lily bud sepal nuclei, but is different in sea urchin sperm nuclei. Histone H1 may not be present in significant amounts in lily bud sepals or may not be present at all in yeast (17,28,(32)(33)(34)(35). Since H1-depleted chromatin under the ionic conditions used in this work is unfolded (36) and the strength of studied histone-DNA contacts in the nucleosomal core in chromatin depleted of linker histones is similar to that observed in lily and yeast nuclei, a significant portion of chromatin in yeast and lily nuclei, prepared as described (17), might also be unfolded.…”

Chemical approaches to the study of supramolecular biological structures with chromatin as an example

“…The similarity of the primary organisation of nucleosomes isolated from different sources provides support for their conservative structure. 24,25,36 The crucial role of histone H1 in chromatin condensation and maintenance of the 30 nm fibril, which is the next hierarchic level of chromatin organisation, was demonstrated in early studies of Georgiev et al 37 The zero-length cross-linking method allowed one to establish that DNA of chromatin from Drosophila embryos is bound simultaneously with histone H1 and core histones. 38,39 It is known that the linker histone H1/H5 has three structurally and functionally different domains, viz., a central globular domain which is evolutionarily the most conservative, a relatively short N-terminal domain and a highly basic lengthy C-terminal domain (terminal domains are the most variable parts of the histone).…”