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Hum Mol Genet. 2014 Mar 15;23(6):1506-15. doi: 10.1093/hmg/ddt537. Epub 2013 Nov 7.

New Lmna knock-in mice provide a molecular mechanism for the 'segmental aging' in Hutchinson-Gilford progeria syndrome.

Author information

1
Molecular Biology Institute.

Abstract

Lamins A and C (products of the LMNA gene) are found in roughly equal amounts in peripheral tissues, but the brain produces mainly lamin C and little lamin A. In HeLa cells and fibroblasts, the expression of prelamin A (the precursor to lamin A) can be reduced by miR-9, but the relevance of those cell culture studies to lamin A regulation in the brain was unclear. To address this issue, we created two new Lmna knock-in alleles, one (Lmna(PLAO-5NT)) with a 5-bp mutation in a predicted miR-9 binding site in prelamin A's 3' UTR, and a second (Lmna(PLAO-UTR)) in which prelamin A's 3' UTR was replaced with lamin C's 3' UTR. Neither allele had significant effects on lamin A levels in peripheral tissues; however, both substantially increased prelamin A transcript levels and lamin A protein levels in the cerebral cortex and the cerebellum. The increase in lamin A expression in the brain was more pronounced with the Lmna(PLAO-UTR) allele than with the Lmna(PLAO-5NT) allele. With both alleles, the increased expression of prelamin A transcripts and lamin A protein was greater in the cerebral cortex than in the cerebellum. Our studies demonstrate the in vivo importance of prelamin A's 3' UTR and its miR-9 binding site in regulating lamin A expression in the brain. The reduced expression of prelamin A in the brain likely explains why children with Hutchinson-Gilford progeria syndrome (a progeroid syndrome caused by a mutant form of prelamin A) are spared from neurodegenerative disease.

PMID:
24203701
PMCID:
PMC3929089
DOI:
10.1093/hmg/ddt537
[Indexed for MEDLINE]
Free PMC Article

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