RETROVIRUS-MEDIATED GENE-TRANSFER OF ORNITHINE-DELTA-AMINOTRANSFERASEINTO KERATINOCYTES FROM GYRATE ATROPHY PATIENTS

Gyrate atrophy is a progressive blindness associated with deficiency o f ornithine aminotransferase (OAT), The strategy of using an autologou s keratinocyte graft, modified to express high levels of OAT as an orn ithine-catabolizing skin-based enzyme sink, is investigated, Two OAT-c ontaining retroviral vectors were constructed with or without a resist ance gene. When packaged in a retroviral vector particle generated wit h the gibbon ape leukemia (GALV) virus envelope (PG13), these vectors could readily transduce >50% of target keratinocytes. The transduced k eratinocytes in culture expressed up to 75-fold more OAT than normal c ontrol keratinocytes and these gene-modified cells extracted [C-14]orn ithine more efficiently than controls, The vector prepared without neo transduced cells more efficiently and led to higher levels of OAT exp ression than the neo-containing vector, Ornithine catabolism was maint ained at high levels when the transduced patient keratinocytes were di fferentiated in vitro as a multilayered cutaneous organoid.