We have constructed interspecific somatic cell hybrids between a temperature-sensitive (ts) mutant cell line of mouse FM3A cells, ts85, that has a heat-labile ubiquitin-activating enzyme (E1) and a human diploid fibroblast cell line, IMR-90. A hybrid clone that could grow stably at a nonpermissive temperature (39 °C) was obtained. Segregation of the hybrid cells at a permissive temperature (33 °C) gave rise to temperature-sensitive clones. The electrophoresis of extracted histones and karyotype analysis of the segregants revealed a close correlation of the ability to grow at 39 °C, the presence of uH2A (ubiquitin-H2A semihistone) at 39 °C, and the presence of the human X chromosome. One of the hybrid clones that could grow at the nonpermissive temperature contained the X chromosome as the only human chromosome. The sodium dodecyl sulfate-polyacrylamide gel electrophoretic pattern of affinity-purified E1 showed that this hybrid clone contained both human and mouse type E1. Thus we conclude that the functional gene for human E1 is located on the X chromosome. © 1991.
Kudo, M., Sugasawa, K., Hori, T. aki, Enomoto, T., Hanaoka, F., & Ui, M. (1991). Human ubiquitin-activating enzyme (E1): Compensation for heat-labile mouse E1 and its gene localization on the X chromosome. Experimental Cell Research, 192(1), 110–117. https://doi.org/10.1016/0014-4827(91)90164-P