Northern blot and 5'RACE analysis of human 3'UTR4. (A) Fetal and adult multiple-tissue Northern blots hybridized with a riboprobe detecting a region between PAS3 and PAS4 of the human 3'UTR. Arrows indicate MID1 transcripts. (B) 5'RACE products obtained with primers located downstream of PAS3. The nucleotide sequences of 5'RACE products have been submitted to Genbank with accession numbers EF532594, EF532595, EF532596.