SMN protein analysis in fibroblast, amniocyte and CVS cultures from spinal muscular atrophy patients and its relevance for diagnosis.
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by the homozygous absence of the telomeric copy of the survival motor neuron (SMNt) gene, due to deletion, gene conversion or point mutation. SMNt and its homologous centromeric copy (SMNc) encode the SMN protein, which is diffusely present in the cytoplasm and in dot-like structures, called gems, in the nucleus. We have studied the SMN protein in different cell cultures, including fibroblasts, amniocytes and CVS cells from SMA individuals and controls. By immunofluorescence analysis we found a marked reduction in the number of gems in fibroblasts, amniocytes and chorionic villus cells of all SMA patients and foetuses, independent of the type of the genetic defect. We also show that immunolocalisation of the SMN protein may be a useful tool for the characterisation of particular patients of uncertain molecular diagnosis.
Patrizi
A L
AL
Institute of Medical Genetics, Catholic University, Rome, Italy.
Tiziano
F
F
Zappata
S
S
Donati
M A
MA
Neri
G
G
Brahe
C
C
D000653:Amniotic Fluid / Q000166:cytology / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D002824:Chorionic Villi / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D009134:Muscular Atrophy, Spinal / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D016601:RNA-Binding Proteins; D055532:SMN Complex Proteins; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein
D017362:Cyclic AMP Response Element-Binding Protein; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D055532:SMN Complex Proteins; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein