the present results suggest that ( 1 ) t4 endonuclease molecules were inserted effectively into the cells by the interaction of hvj with the cell membranes , ( 2 ) the enzyme was functional on human chromosomal dna which had been damaged by uv irradiation in the viable cells , ( 3 ) all the studied groups of xeroderma pigmentosum ( `` '' variant '' '' was not tested ) were defective in the first step ( incision ) of excision repair .
C0007634
cells
C0007603
cell membranes