Northern blot analysis for USP17 subfamily members in human tissues and RT-PCR analysis in human tumor cell lines. (A) Northern blot analysis was carried out to investigate the expression level of USP17 subfamily members in human tissues. The 5' 500 bp- and 3' 1 kb-probes of USP17L were used. The multiple transcript sizes of USP17 mRNA including 1.6 kb were detected. The same blot was probed with the human β-actin as a loading control. (B) Global expression of USP17 subfamily members in various cancer cell lines.