Table 3.

Effect of control PNAs on Xist body formation in female ES cells

PNA	No signal	Xist double dot	Xist body	Number nuclei	Percent Xist bodies
(−)	17	196	318	531	60
1290	32	207	359	598	60
1252	20	208	307	535	57

We wished to test whether PNA administration by itself could alter the capacity of ES cells to differentiate normally and form Xist bodies. We evaluated scrambled sequence (pWS1252) or mismatched sequence (pWS1290) PNAs for their capacity to prevent Xist body formation during differentiation of female ES cells (see Experimental Procedures). Female ES cells were differentiated and treated with PNA–transportan conjugates for 6 days. The cells were then fixed and assayed for the number of Xist bodies by RNA-FISH.