Cell Nuclei Spin in the Absence of Lamin B1

doi:10.1074/jbc.M611094200

Cell Nuclei Spin in the Absence of Lamin B1^*

^{^‡}Cardiovascular Division, Brigham and Women's Hospital, Cambridge, Massachusetts 02139, the ^{^∥}Laboratory of Cancer and Developmental Biology, NCI, National Institutes of Health, Frederick, Maryland 21702, the ^{^¶}Department of Medicine, University of California, Los Angeles, California 90095, the ^{^§}Department of Human Genetics, University of California, Los Angeles, California 90073, and the ^{^**}Department of Medicine, Division of Cardiovascular Medicine, University of Cambridge, Box 110, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, United Kingdom

1 To whom correspondence should be addressed: Partners Research Facility-Rm. 283, 65 Landsdowne St., Cambridge, MA 02139. Tel.: 617-768-8273; Fax: 617-768-8280; E-mail: jlammerding{at}rics.bwh.harvard.edu.

Abstract

Mutations of the nuclear lamins cause a wide range of human diseases, including Emery-Dreifuss muscular dystrophy and Hutchinson-Gilford progeria syndrome. Defects in A-type lamins reduce nuclear structural integrity and affect transcriptional regulation, but few data exist on the biological role of B-type lamins. To assess the functional importance of lamin B1, we examined nuclear dynamics in fibroblasts from Lmnb1^Δ/Δ and wild-type littermate embryos by time-lapse videomicroscopy. Here, we report that Lmnb1^Δ/Δ cells displayed striking nuclear rotation, with ∼90% of Lmnb1^Δ/Δ nuclei rotating at least 90° during an 8-h period. The rotation involved the nuclear interior as well as the nuclear envelope. The rotation of nuclei required an intact cytoskeletal network and was eliminated by expressing lamin B1 in cells. Nuclear rotation could also be abolished by expressing larger nesprin isoforms with long spectrin repeats. These findings demonstrate that lamin B1 serves a fundamental role within the nuclear envelope: anchoring the nucleus to the cytoskeleton.

Footnotes

↵² The abbreviations used are: NPC, nuclear pore complex; MEF, mouse embryo fibroblast; LBR, lamin B receptor; KASH, Klarsicht/ANC-1/Syne-1 homology; GFP, green fluorescent protein; EGFP, enhanced GFP; RFP, red fluorescent protein; ER, endoplasmic reticulum; Az, sodium azide; DOG, 2-deoxyglucose; Bis-Tris, 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-propane-1,3-diol.
↵^* This work was supported by National Institutes of Health Grants HL073809, HL64858, AR050200, and HL082792, the American Heart Association Grant 0635359N, the Progeria Research Foundation, March of Dimes, and a NRSA postdoctoral fellowship HL079862 (to J. Y. J.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵ The on-line version of this article (available at http://www.jbc.org) contains supplemental videos S1-S15, Figs. S1-S3, and additional text.
- Received December 4, 2006.
- Revision received May 1, 2007.