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The alpha‐helical rod domain of human lamins A and C contains a chromatin binding site.
Author(s) -
Glass C.A.,
Glass J.R.,
Taniura H.,
Hasel K.W.,
Blevitt J.M.,
Gerace L.
Publication year - 1993
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1993.tb06126.x
Subject(s) - experimental biology , library science , biology , computational biology , computer science
We examined regions of human lamins A and C involved in binding to surfaces of mitotic chromosomes. An Escherichia coli expression system was used to produce full‐length lamin A and lamin C, and truncated lamins retaining the central alpha‐helical rod domain (residues 34–388) but lacking various amounts of the amino‐terminal ‘head’ and carboxy‐terminal ‘tail’ domains. We found that lamin A, lamin C and lamin fragments lacking the head domain and tail sequences distal to residue 431 efficiently assembled into paracrystals and strongly associated with mitotic chromosomes. Furthermore, the lamin rod domain also associated with chromosomes, although efficient chromosome coating required the pH 5–6 conditions needed to assemble the rod into higher order structures. Biochemical assays showed that chromosomes substantially reduced the critical concentration for assembly of lamin polypeptides into pelletable structures. Association of the lamin rod with chromosomes was abolished by pretrypsinization of chromosomes, and was not seen for vimentin (which possesses a similar rod domain). These data demonstrate that the alpha‐helical rod of lamins A and C contains a specific chromosome binding site. Hence, the central rod domain of intermediate filament proteins can be involved in interactions with other cellular structures as well as in filament assembly.