Physical mapping of new DNA probes near the fragile X mutation (FRAXA) by using a panel of cell lines.
The fragile X syndrome is a very common disorder, but there has been little progress toward isolating the fragile X mutation (FRAXA). We describe a panel of 14 somatic cell hybrid lines, lymphoblastoid cell lines, and peripheral lymphocytes with X-chromosome translocation or deletion breakpoints near FRAXA. The locations of the breakpoints were defined with 16 established probes between pX45d (DXS100) and St14-1 (DXS52). Seven of the cell lines had breakpoints between the probes RN1 (DXS369) and U6.2 (DXS304), which flank FRAXA at distances of 3-5 centimorgans. The panel of cell lines was used to localize 16 new DNA probes in this region. Six of the probes-VK16, VK18, VK23, VK24, VK37, and VK47--detected loci near FRAXA, and it was possible to order both the X-chromosome breakpoints and the probes in relation to FRAXA. The order of probes and loci near FRAXA is cen-RN1,VK24-VK47-VK23-VK16,FRAXA-++ +VK21A-VK18-IDS-VK37-U6.2-qter. The breakpoints near FRAXA are sufficiently close together that probes localized with this panel can be linked on a large-scale restriction map by pulsed-field gel electrophoresis. This panel of cell lines will be valuable in rapidly localizing other probes near FRAXA.
Suthers
G K
GK
Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, South Australia.
Hyland
V J
VJ
Callen
D F
DF
Oberle
I
I
Rocchi
M
M
Thomas
N S
NS
Morris
C P
CP
Schwartz
C E
CE
Schmidt
M
M
Ropers
H H
HH
D000818:Animals; D002460:Cell Line; D002871:Chromosome Banding; D006224:Cricetinae; D015342:DNA Probes; D005260:Female; D005600:Fragile X Syndrome / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D006822:Hybrid Cells; D008297:Male; D051379:Mice; D009154:Mutation; D015183:Restriction Mapping; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome
D015342:DNA Probes; D005819:Genetic Markers