BMC Cancer 2006, 6:132 http://www.biomedcentral.com/1471-2407/6/132 FFPigGuSretra1nscription initiation rate and start sites in CCRF-CEM and NALM6 cells FPGS transcription initiation rate and start sites in CCRF-CEM and NALM6 cells. (A) Nuclear run-on assays. Intact nuclei were isolated from CCRF-CEM and NALM6 cells, and nascent RNA transcripts were labeled with [α-32P]UTP, purified, and hybridized to 1 µg of FPGS and 18S cDNAs blotted on nitrocellulose membrane. Integration densitometry values of FPGS and 18S signals were determined using the Gel-Pro program. Bars represent the mean of four independent experi- ments ± S.E.M. Comparison of transcription rates were achieved using a Student's t-test (*, p < 0.05). (B) 5'-RACE products of FPGS mRNA from RCH (RCH-ACV), REH, NALM6, CEM (CCRF-CEM) and K562 cells are indicated. The lanes "CTRL" and "MW" represent negative control and the 100 bp DNA ladder, respectively. See Materials and Methods for details. acterized by nucleotide sequence analysis to encode mito- chondrial/cytosolic and cytosolic FPGS, respectively. Long fragments were detected in CCRF-CEM (T-ALL) whereas both short and long fragments were amplified from NALM6 and REH (Bp-ALL) (Figure 1B). Therefore, both Bp-ALL and T-ALL cells use the same promoter to tran- scribe FPGS mRNA but lineage differences in mRNA tran- scripts exist. Page 5 of 12 (page number not for citation purposes)