Northern blot analysis of AF6q21 transcription in several human leukemic cell lines (left) and several human tissues (right) using a cDNA probe corresponding to almost all of the AF6q21 ORF. Control hybridization with an actin probe is shown at bottom. The position of size markers is indicated. Additional smaller species are detected in some samples upon longer exposure (data not shown). They could be due to variation in alternate splicing within the AF6q21 gene or to expression of a homologous gene such as the one postulated for chromosome 17. Loading is as follows: Left panel: 1, HL60; 2, HeLa; 3, K562; 4, MOLT4; 5, Raji; 6, SW480; 7, A549; 8, G361. Right panel: 1, heart; 2, brain; 3, placenta; 4, lung; 5, liver; 6, skeletal muscle; 7, kidney; 8, pancreas.