Barton J W, Hart I M, Patterson D
Eleanor Rossevelt Institute for Cancer Research, Denver, Colorado 80206.
Genomics. 1991 Feb;9(2):314-21. doi: 10.1016/0888-7543(91)90259-h.
The human phosphoribosylaminoimidazole (AIR) carboxylase locus has been until this report one of the genes encoding purine biosynthetic enzymes that had not been assigned to an individual human chromosome. Characterization of Chinese hamster ovary (CHO) cell mutant Ade-D showed that the cell line was unable to produce IMP and accumulated AIR. CHO Ade-D cells were fused with normal human lymphocytes utilizing inactivated Sendai virus and the resulting hybrid cell lines were selected for purine prototrophy. Cytogenetic analysis showed a 100% concordance value for chromosome 4. Two of the isolated subclones contained only the long arm of chromosome 4 translocated onto a CHO chromosome, providing evidence for a regional assignment of the Ade-D gene to the long arm of chromosome 4. Two of the subclones containing chromosome 4 were subjected to the BrdU visible light segregation. All of the isolated purine auxotrophic cell lines showed a loss of the q arm of chromosome 4. The localization of the Ade-D locus to the long arm of chromosome 4 may reveal further clustering of the mammalian purine genes since the Ade-A locus has previously been regionally assigned to 4pter-q21.
直到本报告发表时，人类磷酸核糖氨基咪唑（AIR）羧化酶基因座仍是编码嘌呤生物合成酶但尚未定位到某一条人类染色体上的基因之一。对中国仓鼠卵巢（CHO）细胞突变体Ade-D的特性分析表明，该细胞系无法产生肌苷一磷酸（IMP）并积累了AIR。利用灭活的仙台病毒将CHO Ade-D细胞与正常人淋巴细胞融合，并选择所得的杂交细胞系用于嘌呤原养型培养。细胞遗传学分析表明，第4号染色体的一致性值为100%。两个分离出的亚克隆仅包含易位到一条CHO染色体上的第4号染色体长臂，这为将Ade-D基因区域定位到第4号染色体长臂提供了证据。对两个含有第4号染色体的亚克隆进行了5-溴脱氧尿苷（BrdU）可见光分离分析。所有分离出的嘌呤营养缺陷型细胞系均显示第4号染色体q臂缺失。由于之前已将Ade-A基因座区域定位到4pter-q21，将Ade-D基因座定位到第4号染色体长臂可能揭示哺乳动物嘌呤基因的进一步聚类情况。
