Chromate Resistance

In interspecific human-Chinese hamster ovary (CHO) cell hybrids, Dana and Wasmuth (1982) showed that resistance to concentrations of sodium chromate that normally are cytotoxic is determined by a gene on chromosome 5 in man. The biochemical nature of the mutation that results in chromate resistance is unknown. Emetine resistance (EMTB; 130620) and temperature-sensitive leucyl-tRNA synthetase (LEUS; 151350) are also determined by genes on human chromosome 5. The synteny of the 3 loci has been long maintained in evolution, evidenced by the fact that the 3 loci are linked on the long arm of Chinese hamster chromosome 2. Dana and Wasmuth (1982) subjected Chinese hamster-human interspecific hybrid cells, which contained human chromosome 5 and expressed the 4 syntenic genes LEUS, HEXB (606873), EMTB, and CHR, to selective conditions requiring them to retain the LEUS gene but lose either the EMTB or CHR gene. Using cytogenetic and biochemical analyses of spontaneous segregants, which arose primarily by terminal deletions of various portions of 5q, Dana and Wasmuth (1982) concluded that the order and specific locations of the linked genes are: LEUS, 5pter-5q1; HEXB, 5q13; EMTB, 5q23-5q35; and CHR, 5q35. The product of the CHR locus appears to be involved in sulfate transport (Dana and Wasmuth, 1982).