Lamin B1 is required for mouse development and nuclear integrity

• Lamins are key structural components of the nuclear lamina, an intermediate filament meshwork that lies beneath the inner nuclear membrane. Lamins play a role in nuclear architecture, DNA replication, and gene expression. Mutations affecting A-type lamins have been associated with a variety of human diseases, including muscular dystrophy, cardiomyopathy, lipodystrophy, and progeria, but mutations in B-type lamins have never been identified in humans or in experimental animals. To investigate the in vivo function of lamin B1, the major B-type lamin, we generated mice with an insertional mutation in Lmnb1. The mutation resulted in the synthesis of a mutant lamin B1 protein lacking several key functional domains, including a portion of the rod domain, the nuclear localization signal, and the CAAX motif (the carboxyl-terminal signal for farnesylation). Homozygous Lmnb1 mutant mice survived embryonic development but died at birth with defects in lung and bone. Fibroblasts from mutant embryos grew under standard cell-culture conditions but displayed grossly misshapen nuclei, impaired differentiation, increased polyploidy, and premature senescence. Thus, the lamin B1 mutant mice provide evidence for a broad and nonredundant function of lamin B1 in mammalian development. These mutant mice and cell lines derived from them will be useful models for studying the role of the nuclear lamina in various cellular processes.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

Keyword

Djurmodeller

CAAX proteiner

Animals

Bone and Bones/abnormalities

Cells

Cultured

Embryonic and Fetal Development/physiology

Fibroblasts/cytology

*Gene Expression Regulation

Developmental

Genes

Lethal

Lamin Type B/*genetics/*metabolism

Lung/abnormalities

Mice

Mice

Knockout

Mutagenesis

Insertional

Nuclear Lamina/pathology/*physiology

Ossification

Heterotopic/physiopathology

Research Support

U.S. Gov't

P.H.S.

Stem Cells/cytology

Publication and Content Type

ref (subject category)

art (subject category)