Northern hybridization.

(A) The first hybridization. With full length ETV6 cDNA probe, 6.2 kb transcript (small arrow) was detected in the HT93A, HL60, and K562 cells, but an additional longer transcript (large arrow) was detected only in the HT93A cells. This abnormal transcript was hybridized with A-I (ETV6 exons 1-5) probe but not with A-II (ETV6 exons 6-8) probe. (B) The second hybridization. With theARG 3′ probe, an abnormal transcript (black arrow) was detected only in the HT93A cells at the same position as the abnormalETV6 transcript in the first hybridization. The 12.5 kb normal transcript of ARG (white arrow) was also detected in HT93A cells and control cells. This abnormal band was hybridized only withETV6 exon 1A probe.