LBR mutation and nuclear envelope defects in a patient affected with Reynolds syndrome.
BACKGROUND Lamins are proteins of the nuclear envelope involved in 'laminopathies', an heterogeneous group of diseases sharing clinical similarities with systemic sclerosis (SSc). Methods In this context, a search was undertaken for mutations in LMNA, encoding Lamins A/C, and ZMPSTE24, LBR, LMNB1, LMNB2, MAN1, SYNE1a and LAP2, encoding Lamins A/C molecular partners, in a Caucasian woman affected with Reynolds syndrome, a particular nosologic entity specifically associating limited cutaneous SSc and primary biliary cirrhosis. RESULTS Coding regions and intron-exon boundaries of these genes were PCR amplified and sequenced, revealing a single heterozygous missense mutation in LBR exon 9 (c.1114C/T; p.R372C). This variant was absent in 400 control chromosomes. The mutation was predicted to induce a change in Lamin B receptor (LBR) tertiary structure and molecular interactions by bioinformatic tools. Further functional explorations were performed on the patient's fibroblasts and lymphoblastoid cell lines. On the latter, the expression levels of LBR, Lamins A/C, Lamin B1, Lamin B2, and HP1a were conserved. Conversely, in the patient's skin fibroblasts, LBR and the aforementioned molecular partners showed dramatically reduced or abolished expression levels. The immunofluorescence analyses performed on both cell lines corroborated these findings. CONCLUSION The fibroblast specific abnormalities observed suggest that this particular LBR mutation might have dominant negative deleterious effects in a tissue specific fashion, possibly through the perturbation of the interactions or stability of the nuclear envelope protein network. LBR mutations might thus be associated with Reynolds syndrome.
Service de Dermatologie, Hôpital Ste Marguerite, Marseille, France.
Caroline
C
Gaudy-Marqueste
Patrice
P
Roll
Vera
V
Esteves-Vieira
Pierre-Jean
PJ
Weiller
Jean Jacques
JJ
Grob
Pierre
P
Cau
Nicolas
N
Lévy
Annachiara
A
De Sandre-Giovannoli
D000368:Aged; D001483:Base Sequence; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008105:Liver Cirrhosis, Biliary / Q000150:complications / Q000235:genetics*; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012595:Scleroderma, Systemic / Q000150:complications / Q000235:genetics*; D013577:Syndrome; D000097682:Lamin B Receptor
D018160:Receptors, Cytoplasmic and Nuclear; D000097682:Lamin B Receptor