Physical localization of 70 polymorphic markers to human chromosome 5 by fluorescence in situ hybridization

Physical and linkage mapping of the bovine genome with cosmids

We have initiated a mapping strategy using cosmid clones to chromosomally anchor a high-resolution bovine genetic linkage map. Ten cosmids containing microsatellites were assigned to bovine chromosomes by fluorescence in situ suppression hybridization (FISH). Four cosmid clones, three of which contain an informative microsatellite, were assigned to autosomes 5, 13, 24, and 28. The assignment to autosome 13 anchors bovine syntenic group U11. Two additional cosmid clones, each containing informative microsatellites, are assigned to autosomes 9 and 29, anchoring bovine linkage groups U2 and U8, respectively. Four cosmid clones, three of which contain informative microsatellites, also provide the first assignment to autosome 25, anchoring bovine syntenic group U7 and orienting the corresponding linkage group relative to the centromere.

Cytogenetic and molecular delineation of the smallest commonly deleted region of chromosome 5 in malignant myeloid diseases

Loss of a whole chromosome 5 or a deletion of its long arm (5q) is a recurring abnormality in malignant myeloid neoplasms. To determine the location of genes on 5q that may be involved in leukemogenesis, we examined the deleted chromosome 5 homologs in a series of 135 patients with malignant myeloid diseases. By comparing the breakpoints, we identified a small segment of 5q, consisting of band 5q31, that was deleted in each patient. This segment has been termed the critical region. Distal 5q contains a number of genes encoding growth factors, hormone receptors, and proteins involved in signal transduction or transcriptional regulation. These include several genes that are good candidates for a tumor-suppressor gene, as well as the genes encoding five hematopoietic growth factors (CSF2, IL3, IL4, IL5, and IL9). By using fluorescence in situ hybridization, we have refined the localization of these genes to 5q31.1 and have determined the order of these genes and of other markers within 5q31. By hybridizing probes to metaphase cells with overlapping deletions involving 5q31, we have narrowed the critical region to a small segment of 5q31 containing the EGR1 gene. The five hematopoietic growth factor genes and seven other genes are excluded from this region. The EGR1 gene was not deleted in nine other patients with acute myeloid leukemia who did not have abnormalities of chromosome 5. By physical mapping, the minimum size of the critical region was estimated to be 2.8 megabases. This cytogenetic map of 5q31, together with the molecular characterization of the critical region, will facilitate the identification of a putative tumor-suppressor gene in this band.