Expression analysis of the BTF family. (A) Northern blot analysis of representative members of the two groups of BTF proteins, BTF1 and BTF5. BTF1 hybridized to all tissues on the blot as a major transcript at 2.9 kb. BTF5 hybridizes to several transcripts ranging between 4.0 and 3.1 kb and displays as a similar expression profile to BTF1, with the exception of less expression in the brain. Autoradiography was for 24 hr. The β-actin hybridization shows the variation in poly(A)+ RNA between the lanes. Autoradiography was for 1 hr. (B) RT–PCR analysis confirms that the expression of both genes is widespread. Included in the (+) lane are BTF1 and BTF5 cDNAs as positive controls, the (−) lane represents the no-DNA control. Amplification using primers for the RFP gene (Isomura et al. 1992) controls for the integrity of the cDNA. All first strand cDNAs were checked for contaminating genomic DNA amplification by carrying out an identical experiment excluding the reverse transcriptase. In all cases, no amplification was obtained (data not shown).
