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Expression of an LMNA-N195K variant of A-type lamins results in cardiac conduction defects and death in mice.

Authors: Mounkes, LC  Kozlov, SV  Rottman, JN  Stewart, CL 
Citation: Mounkes LC, etal., Hum Mol Genet. 2005 Aug 1;14(15):2167-80. Epub 2005 Jun 22.
Pubmed: (View Article at PubMed) PMID:15972724
DOI: Full-text: DOI:10.1093/hmg/ddi221

The nuclear lamina is an approximately 10 nm thick proteinaceous layer underlying the inner nuclear membrane. The A-type lamins, nuclear intermediate filament proteins encoded by the LMNA gene, are basic components of the nuclear lamina. Mutations in LMNA are associated with the laminopathies, congenital diseases affecting tissue regeneration and homeostasis. One of these laminopathies associated with missense mutations in LMNA is dilated cardiomyopathy with conduction system disease (DCM-CD1). To understand how the laminopathies arise from different mutations in a single gene, we derived a mouse line by homologous recombination expressing the Lmna-N195K variant of the A-type lamins with an asparagine-to-lysine substitution at amino acid 195, which causes DCM in humans. This mouse line shows characteristics consistent with DCM-CD1. Continuous electrocardiographic monitoring of cardiac activity demonstrated that LmnaN195K/N195K mice die at an early age due to arrhythmia. By immunofluorescence and western analysis, the transcription factor Hf1b/Sp4 and the gap junction proteins connexin 40 and connexin 43 were misexpressed and/or mislocalized in LmnaN195K/N195K hearts. Desmin staining revealed a loss of organization at sarcomeres and intercalated disks. Mutations within the LMNA gene may therefore cause cardiomyopathy by disrupting the internal organization of the cardiomyocyte and/or altering the expression of transcription factors essential to normal cardiac development, aging or function.

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CRRD Object Information
CRRD ID: 1581308
Created: 2006-09-25
Species: All species
Last Modified: 2006-09-25
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.