HRAS1-selected chromosome transfer generates markers that colocalize aniridia- and genitourinary dysplasia-associated translocation breakpoints and the Wilms tumor gene within band 11p13.

Abstract

We show that chromosome-mediated gene transfer can provide an enriched source of DNA markers for predetermined, subchromosomal regions of the human genome. Forty-four human DNA recombinants isolated from a HRASI-selected chromosome-mediated gene transformant map exclusively to chromosome 11, with several sublocalizing to the Wilms tumor region at llpl3. We present a detailed molecular map of the deletion chromosomes 11 from five WAGR (Wilms tumor/aniridia/genitourinary abnormalities/ mental retardation) syndrome patients, three of which are at the limits of cytogenetic resolution but shown here to be molecularly distinguishable and overlapping. We can define ten distinct regions of the short arm of chromosome 11, five of which subdivide band lipl3. We also map two independent llpl3 translocation breakpoints to within the smallest region of overlap defined by the WAGR deletions. The first comes from a patient with familial aniridia, and the second from a patient with Potter facies and genitourinary dysplasia. The close similarities in map location and affected cell lineage for Wilms tumor and genitourinary dysplasia suggest that they may be alternative manifestations of mutation at the same locus.The association of aniridia, genitourinary abnormalities, and mental retardation with Wilms tumor (WAGR syndrome; genetic locus WAGR) is well established (1, 2). Cytogenetic analysis of independent WAGR syndrome patients has localized the relevant genetic region to band llpl3 (3). We (4) and others (5-8) have utilized available DNA probes and expressed protein markers to start to define the molecular extent of the various deletions. In most studies, only one patient has been examined (5-7) or the deletions have been large and therefore likely to show loss of markers that map some distance from the disease-related genes (8). We now attempt to distinguish the smaller deletions, those which take us beyond the resolving power of cytogenetic analysis towards defining the smallest region of overlap that is within reach of complete molecular analysis. We make use of five independent WAGR deletion hybrids, three of which are at the limit of cytogenetic resolution and involve only part of band llpl3.The short arm of human chromosome 11 (lip) is one of the better mapped regions of the genome (9, 10), but there is still a relative dearth of genetic markers that map within even the larger WAGR syndrome deletions (4, 8). The genes encoding erythrocyte catalase (CAT) and two cell surface markers, MIC4 and MIC11 (synonymous with MIC1), all map to band llpl3 and are closely associated with WAGR but not invariably deleted (4, 8). Most recently (8), the /3 subunit of follicle-stimulating hormone (FSHB) has been shown to map close to the aniridia and Wilms tumor genes. Of the anonymous DNA markers mapped to the short arm of chromosome 11, the majority derive from a somatic cell hybrid considered to retain lip material as the sole human component (11). However, none of these markers has been found to map as close to WAGR as CAT or F...

Molecular definition of de novo and genetically transmitted WAGR-associated rearrangements of 11p13

“…Patient SOA is therefore one of the very few cases of WAGR syndrome reported without a deletion of the segment carrying the gene for CAT (van Heyningen et al. 1985;Glaser et al, 1986;Brunsetal., 1987 Cytogenetic analyses and DNA studies of such patients with WAGR syndrome and different partial deletions of band 11 p 13 allow further dissection of the responsible chromosome region into several subregions (van Heyningen et al, 1985;Glaser et al, 1986;B runsetaL 1987;Cowell and Little, 1987;Davis et al, 1987;Huerre-Jeanpierre et al, 1987;Porteous et al, 1987;Bickmore et al, 1988;Lewis et al, 1988). A molecular analysis of these patients with new markers will provide a better physical map for this chro mosomal region.…”

Somatic cell hybrid and long-range physical mapping of 11p13 microdissected genomic clones.

“…The observation that most of these WAGR and AGR children are born with a hemizygous interstitial deletion of 11p13 (6,7) has led to the speculation that chromosome band 11p13 houses not only the aniridia gene and a gene predisposing to Wilms tumor but also an unknown number of additional genes necessary for normal development of the kidney, iris, genitourinary tract, and mental function. In fact, a discrete, apparently autosomal dominant locus in 11p13 that may be responsible for complete renal agenesis has been described (8).…”

“…For some, the source of clones was a Livermore Laboratory chromosome 11 library (12-15); others generated reduced chromosome human-rodent somatic cell hybrids (8,16,17), from which genomic libraries were constructed and human clones were identified by hybridization to human repetitive sequence probes. Both of these probe isolation strategies require that the markers be mapped to the region of interest on a panel of somatic cell hybrids retaining deletions or translocations in the region of interest and share the disadvantage of only recovering probes at the same percentage as the region of interest is to the total starting material.…”

Reassessment of breakpoints in chromosome 11p15

“…N Y X 3 .1. is a m ouse m yelom a x hu m an lym phoblastoid hybrid from a W A G R patient. C ytogenetic analysis dem o n strated a deletion extending from 11 p i 3 to 11 p i 5.4 (Porteous et al, 1987). T he proxim al breakpoint o f the deletion lies distal to p2G8 (D l 1S50) (P orteous e ta l.. 1987), whereas LDH A m aps beyond the distal break point (Scrable et al, 1990), which unam biguously m aps to 1 l p l 5.1->p!4 (Ju nien and van H eyningen, 1991).…”