Table 1.

Transcription is required for CFS expression at FHIT in a gene-specific manner

	# of gaps and breaks/cells scored (%)
Cells	FRA3B (FHIT)	FRA3O (NLGN1)
WT GM11713 + APH	16/50 (32%)	8/50 (16%)
KO Clone 1 + APH	1/50 (2%) **	13/50 (26%)
KO Clone 2 + APH	0/50 (0%) **	10/38 (26%)

WT GM11713 and its promoterless derivatives were subjected to FISH-based CFS analysis at FRA3B and FRA3O. Statistical analysis was by Fisher’s exact test, comparing each clone to WT; **, P < 0.0001. Fifty cells from each cell type without APH treatment were also scored and none showed gaps or breaks at these loci.