Polymerase DNA Directed Alpha 1 (POLa1)

Hanaoka et al. (1985) complemented a temperature-sensitive defect in murine POLA by fusing the defective mouse cells with human cells. A gene present on Xpter-q22 was responsible for correcting the defect. Wang et al. (1985) used a monoclonal antibody that distinguishes human from rodent DNA polymerase alpha to study human-rodent cell hybrids. They mapped the gene to a site near the junction of Xp21.3 and Xp22.1 (perhaps Xp21.12-p21.11) and showed that it is not expressed in an inactive X chromosome. They concluded that POLA is distal to DMD and CGD but proximal to STS. They predicted that mosaic nullisomy in a female resulting from deletion of this gene could not exist and that hemizygosity for deletion of the gene in a male would be lethal because of the essentiality of the gene to the catalytic activity of DNA polymerase alpha.