Genomic organization and structure of CLLU1 transcripts. (A) Organization of genes and ESTs in the 12q21.33 to 12q22 region. Genes above the bar are transcribed from the +strand and genes below from the -strand; gene names and accession numbers for ESTs are indicated. Expression of all the transcripts was analyzed by RT-PCR (Figure 3), and transcripts that were differentially expressed between patients with and without somatic hypermutations are shown in red. Many of the ESTs have been identified in CLL or germinal center B cells (indicated with cll and gcb, respectively). The 3 BAC clones that were used for FISH (Figure 5) are indicated. (B) Identified CLLU1 transcripts. Exons are colored red and black as in panel A, and the putative coding sequence is shown in green; introns are shown as thin black lines; dotted red lines denote that transcripts with the indicated sequences may be present. ^*Transcripts were cloned as cDNAs; other transcripts were detected by RACE or RT-PCR. The sequences of transcripts 1 to 7 have been submitted to the EBI database and given accession numbers AJ845162-8.