title: The effect of the lamin A and its mutants on nuclear structure, cell proliferation, protein stability, and mobility in embryonic cells.
abstract: LMNA gene encodes for nuclear intermediate filament proteins lamin A/C. Mutations in this gene lead to a spectrum of genetic disorders, collectively referred to as laminopathies. Lamin A/C are widely expressed in most differentiated somatic cells but not in early embryos and some undifferentiated cells. To investigate the role of lamin A/C in cell phenotype maintenance and differentiation, which could be a determinant of the pathogenesis of laminopathies, we examined the role played by exogenous lamin A and its mutants in differentiated cell lines (HeLa, NHDF) and less-differentiated HEK 293 cells. We introduced exogenous wild-type and mutated (H222P, L263P, E358K D446V, and ∆50) lamin A into different cell types and analyzed proteins' impact on proliferation, protein mobility, and endogenous nuclear envelope protein distribution. The mutants give rise to a broad spectrum of nuclear phenotypes and relocate lamin C. The mutations ∆50 and D446V enhance proliferation in comparison to wild-type lamin A and control cells, but no changes in exogenous protein mobility measured by FRAP were observed. Interestingly, although transcripts for lamins A and C are at similar level in HEK 293 cells, only lamin C protein is detected in western blots. Also, exogenous lamin A and its mutants, when expressed in HEK 293 cells underwent posttranscriptional processing. Overall, our results provide new insight into the maintenance of lamin A in less-differentiated cells. Embryonic cells are very sensitive to lamin A imbalance, and its upregulation disturbs lamin C, which may influence gene expression and many regulatory pathways.
authors.affiliation: Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383, Wroclaw, Poland.
authors.forename: Katarzyna
authors.identifier: 0000-0002-9716-2393
authors.initials: K
authors.lastname: Piekarowicz
authors.affiliation: Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383, Wroclaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Machowska
authors.affiliation: Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383, Wroclaw, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Dratkiewicz
authors.affiliation: Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383, Wroclaw, Poland.
authors.forename: Daria
authors.initials: D
authors.lastname: Lorek
authors.affiliation: Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5, 02-106, Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Madej-Pilarczyk
authors.affiliation: Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383, Wroclaw, Poland. rzepecki@ibmb.uni.wroc.pl.
authors.forename: Ryszard
authors.initials: R
authors.lastname: Rzepecki
mesh_terms: D002454:Cell Differentiation / Q000235:genetics; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D034904:Lamin Type A / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism; D055550:Protein Stability
chemical_list: D034904:Lamin Type A; C440308:lamin C
keywords: Emery-Dreifuss muscular dystrophy; Human embryonic kidney 293; Hutchinson-Gilford progeria syndrome; Lamin A/C; Laminopathy; Nuclear envelope