The Tn5 and the Streptoalloteichus hindustanus (Sh) ble genes conferring resistance to bleomycin-phleomycin antibiotics have been cloned into a mammalian vector under the RSV-LTR promoter. The resulting plasmids, pUT506 and pUT507 respectively, were used to transfect CHO cells by either the calcium phosphate or the recently described polybrene-DMSO method. Phleomycin- or bleomycin-resistant clones arose with a higher frequency after transfection with pUT507, and pUT507 transfectants were more resistant to both antibiotics than pUT506 transfectants. Phleomycin resistance in pUT507 transfectants was stable and associated with integration of plasmid sequences in genomic DNA. The Sh ble gene, which confers a dominant phleomycin-resistance phenotype, should provide a useful transferable selectable marker in CHO cells as well as in other animal cell lines.

No abstract

In the pig, the linkage group around the halothane gene (HAL), composed of S-GPI-HAL-H-A1BG-PGD, has been assigned to bands p1.2→q2.2 of chromosome 6. In man, ENOl-PGD and APOE-GPI constitute two syntenic groups situated on different chromosomes (1 and 19, respectively). Since GPI and PGD are linked in the pig, we have hybridized the human cDNA probes for ENO1and APOE to pig chromosomes. These markers were assigned to pig chromosome 6, in the q2.2→q2.4 and cen→q2.1 regions, respectively, using in situ hybridization. Since GPI and APOE are situated in the same region, we combined the use of high resolution chromosome analysis and in situ hybridization to give a more precise localization in the q1.2 and q1.2→q2.1.2 regions of chromosome 6. A possible linear order of these genes is proposed.

The pig major histocompatibility complex (SLA) was mapped by in situ hybridization. The probe used was a human cDNA containing most of the coding sequence for HLA-B7. The SLA complex was localized to the region p1.4→q1.2 on chromosome 7.

The TGF beta-1 and PGD loci have been localized by in situ hybridization to the C-greater than q2.1 and q2.2 -greater than q2.5 regions of pig chromosome 6. These assignments confirm that the conversation of syntenic groups around GPI and PGD extends to pigs where these two groups are uniquely found to be linked. Our data also support the hypothesis that the porcine and human inherited malignant hyperthermia syndromes are caused by mutations in homologous genes which map to human chromosome 19q, porcine chromosome 6q and murine chromosome 7.