Table 2.

PCR analysis for lacZ sequences in keratinocyte colonies

Sample	β-gal-negative colonies		β-gal-positive colonies
	Total examined	PCR negative	Total examined	PCR positive
Submerged culture	12	12	5	5
Organotypic culture	9	9	4	4
2 weeks after grafting	13	13	6	5
5 weeks after grafting	19	19	9	9
10 weeks after grafting	12	12	12	12

DNA from a number of keratinocyte colonies was analyzed by PCR for lacZ sequencies. Expression of β-gal correlated with the presence of lacZ sequences, except in one β-gal positive colony that did not contain detectable lacZ sequences. All DNA samples were tested by PCR for the endogenous filaggrin gene and found to be positive.