Cell complementation using Genebridge 4 human:rodent hybrids for physical mapping of novel mitochondrial respiratory chain deficiency genes.
The mapping and identification of respiratory chain deficiency genes is particularly tedious owing to the large number of genes encoding catalytic subunits and involved in respiratory chain (RC) assembly and maintenance. We have developed a functional complementation approach by: (i) growing the patient's fibroblasts in a highly selective medium; and (ii) transferring human chromosome fragments into RC-deficient fibroblasts by microcell-mediated transfer. In the absence of carbohydrates in the culture medium, the deficient cells rapidly disappeared unless they were rescued by a chromosome fragment carrying the disease gene. Microcells prepared from human:rodent Genebridge 4 panel of whole genome radiation hybrids were fused with fibroblast strains of two patients with complex II or I+IV deficiency and allowed to map the disease-causing genes to small intervals (4 and 12 Mb) on chromosomes 12p13 and 7p21, respectively. These intervals are similar to that obtained by genetic linkage analyses in large informative families. The recovery of normal RC enzyme activity in deficient skin fibroblasts supported the relevance of the transferred chromosome fragment in the disease. This approach makes the physical mapping of the disease genes feasible in some sporadic cases of RC deficiency.
De Lonlay
Pascale
P
Unité de Recherches sur les Handicaps Génétiques de l'Enfant (INSERM U393), Service Informatique, Service de Cytogénétique, Hôpital Necker-Enfants Malades, Paris, Généthon, Evry, France.
Mugnier
Claude
C
Sanlaville
Damien
D
Chantrel-Groussard
Karine
K
Bénit
Paule
P
Lebon
Sophie
S
Chrétien
Dominique
D
Kadhom
Noman
N
Saker
Safa
S
Gyapay
Gabor
G
Romana
Serge
S
Weissenbach
Jean
J
Munnich
Arnold
A
Rustin
Pierre
P
Rötig
Agnès
A
D000818:Animals; D004579:Electron Transport / Q000235:genetics* / Q000502:physiology; D005347:Fibroblasts; D006801:Humans; D006822:Hybrid Cells; D066298:In Vitro Techniques; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism*; D028361:Mitochondrial Diseases / Q000235:genetics* / Q000378:metabolism; D032342:Muscle Cells; D020161:Physical Chromosome Mapping