title: Lmo7 is dispensable for skeletal muscle and cardiac function.
abstract: Emery-Dreifuss muscular dystrophy (EDMD) is a degenerative disease primarily affecting skeletal muscles in early childhood as well as cardiac muscle at later stages. EDMD is caused by a number of mutations in genes encoding proteins associated with the nuclear envelope (e.g., Emerin, Lamin A/C, and Nesprin). Recently, a novel protein, Lim-domain only 7 (lmo7) has been reported to play a role in the molecular pathogenesis of EDMD. Prior in vitro and in vivo studies suggested the intriguing possibility that Lmo7 plays a role in skeletal or cardiac muscle pathophysiology. To further understand the in vivo role of Lmo7 in striated muscles, we generated a novel Lmo7-null (lmo7(-/-)) mouse line. Using this mouse line, we examined skeletal and cardiac muscle physiology, as well as the role of Lmo7 in a model of muscular dystrophy and regeneration using the dystrophin-deficient mdx mouse model. Our results demonstrated that lmo7(-/-) mice had no abnormalities in skeletal muscle morphology, physiological function, or regeneration. Cardiac function was also unaffected. Moreover, we found that ablation of lmo7 in mdx mice had no effect on the observed myopathy and muscular regeneration exhibited by mdx mice. Molecular analyses also showed no changes in dystrophin complex factors, MAPK pathway components, and Emerin levels in lmo7 knockout mice. Taken together, we conclude that Lmo7 is dispensable for skeletal muscle and cardiac physiology and pathophysiology.
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Dieu Hung
authors.initials: DH
authors.lastname: Lao
authors.affiliation: University of California San Diego, Department of Orthopedic Surgery, La Jolla, California;
authors.forename: Mary C
authors.initials: MC
authors.lastname: Esparza
authors.affiliation: University of California San Diego, Department of Orthopedic Surgery, La Jolla, California;
authors.forename: Shannon N
authors.initials: SN
authors.lastname: Bremner
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Indroneal
authors.initials: I
authors.lastname: Banerjee
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Jianlin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Jennifer
authors.initials: J
authors.lastname: Veevers
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: William H
authors.initials: WH
authors.lastname: Bradford
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Yusu
authors.initials: Y
authors.lastname: Gu
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Dalton
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Kirk U
authors.initials: KU
authors.lastname: Knowlton
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California;
authors.forename: Kirk L
authors.initials: KL
authors.lastname: Peterson
authors.affiliation: University of California San Diego, Department of Orthopedic Surgery, La Jolla, California; Rehabilitation Institute of Chicago, Chicago, Illinois.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Lieber
authors.affiliation: University of California San Diego, Department of Cardiology, La Jolla, California; juchen@ucsd.edu.
authors.forename: Ju
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D015870:Gene Expression / Q000235:genetics; D006321:Heart / Q000502:physiology*; D060588:LIM Domain Proteins / Q000235:genetics* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000502:physiology*; D020389:Muscular Dystrophy, Emery-Dreifuss / Q000235:genetics / Q000473:pathology*; D009206:Myocardium / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D060588:LIM Domain Proteins; C485492:Lmo7 protein, mouse; D014157:Transcription Factors
keywords: Lim-domain only 7; X-linked muscular dystrophy; cardiac muscle; skeletal muscle