DelK32-lamin A/C has abnormal location and induces incomplete tissue maturation and severe metabolic defects leading to premature death

• Published in: Human molecular genetics Vol. 21; no. 5; pp. 1037 - 1048
• Main Authors: Bertrand, Anne T., Renou, Laure, Papadopoulos, Aurélie, Beuvin, Maud, Lacène, Emmanuelle, Massart, Catherine, Ottolenghi, Chris, Decostre, Valérie, Maron, Sophia, Schlossarek, Saskia, Cattin, Marie-Elodie, Carrier, Lucie, Malissen, Marie, Arimura, Takuro, Bonne, Gisèle
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.03.2012; Oxford University Press (OUP)
• Subjects: Adipocytes - cytology; Adipogenesis; Animals; Animals, Newborn; Biological and medical sciences; Cell Nucleus - metabolism; Embryo, Mammalian; Fundamental and applied biological sciences. Psychology; Gene Knock-In Techniques; Genetics of eukaryotes. Biological and molecular evolution; Growth Disorders - genetics; Growth Disorders - metabolism; Heart - growth & development; Immunology; Lamin Type A - genetics; Lamin Type A - metabolism; Lamin Type B - metabolism; Life Sciences; Liver - metabolism; Metabolic Diseases - genetics; Metabolic Diseases - metabolism; Mice; Molecular and cellular biology; Mortality, Premature; Muscle, Skeletal - anatomy & histology; Muscle, Skeletal - growth & development; Mutant Proteins - genetics; Mutant Proteins - metabolism; Myocytes, Cardiac - cytology; Nuclear Lamina - metabolism; Organ Size; Phenotype; Signal Transduction; Sterol Regulatory Element Binding Protein 1 - metabolism; Transcription, Genetic; Incomplete; Premature; Tissue; Mortality; Genetics; Death; Severe; Metabolism
• ISSN: 0964-6906; 1460-2083; 1460-2083
• DOI: 10.1093/hmg/ddr534

The LMNA gene encodes lamin A/C intermediate filaments that polymerize beneath the nuclear membrane, and are also found in the nucleoplasm in an uncharacterized assembly state. They are thought to have structural functions and regulatory roles in signaling pathways via interaction with transcription factors. Mutations in LMNA have been involved in numerous inherited human diseases, including severe congenital muscular dystrophy (L-CMD). We created the Lmna ΔK32 knock-in mouse harboring a L-CMD mutation. Lmna ΔK32/ΔK32 mice exhibited striated muscle maturation delay and metabolic defects, including reduced adipose tissue and hypoglycemia leading to premature death. The level of mutant proteins was markedly lower in Lmna ΔK32/ΔK32, and while wild-type lamin A/C proteins were progressively relocated from nucleoplasmic foci to the nuclear rim during embryonic development, mutant proteins were maintained in nucleoplasmic foci. In the liver and during adipocyte differentiation, expression of ΔK32-lamin A/C altered sterol regulatory element binding protein 1 (SREBP-1) transcriptional activities. Taken together, our results suggest that lamin A/C relocation at the nuclear lamina seems important for tissue maturation potentially by releasing its inhibitory function on transcriptional factors, including but not restricted to SREBP-1. And importantly, L-CMD patients should be investigated for putative metabolic disorders.