Newly identified Chinese hamster ovary cell mutants defective in peroxisome assembly represent complementation group A of human peroxisome biogenesisdisorders and one novel group in mammals

We isolated peroxisome biogenesis-defective mutants from rat PEX2-transform ed Chinese hamster ovary (CHO) cells, using the 9-(1'-pyrene)nonanol/ultrav iolet method. A total of 18 mutant cell clones showing cytosolic localizati on of catalase were isolated. By complementation group (CG;) analysis by me ans of PEX cDNA transfection and cell fusion, cell mutants, ZP124 and ZP126 , were found to belong to two novel CGs of CHO mutants. Mutants, ZP135 and ZP167, mere also classified to the same CG as ZP124. Further cell fusion an alysis using 12 CGs fibroblasts from patients with peroxisome deficiency di sorders such as Zellweger syndrome revealed that ZP124 belonged to human CG -A, the same group as CC-WI in the United States. ZP126 could not be classi fied to any of human and CHO CGs. These mutants also showed typical peroxis ome assembly-defective phenotypes such as severe loss of catalase latency a nd impaired biogenesis of peroxisomal enzymes. Collectively, ZP124 represen ts CG-A, and ZP126 is in a newly identified CG distinct from the 14 mammali an CGs previously characterized, (C) 1999 Academic Press.