The transcription map of the 13q14 region frequently deleted in B-cell chronic lymphocytic leukemia

Deletions in the region located between the STS markers D13S1168 and D13S25 on chromosome 13 are the most frequent genomic changes in patients with B- cell chronic lymphocytic leukemia (B-CLL). After sequencing of this region, two novel candidate genes were identified: C13orf1 (chromosome 13 open rea ding frame 1) and PLCC (putative large CLL candidate). Analysis of the repe at distribution revealed two subregions differing in composition of repetit ious DNA and gene organization, The interval D13S1168-D13S319 contains 131 Alu repeats accounting for 24.8% of its length, whereas the interval GCT16C 05-D13S25, which is no more than 180 kb away from the former one is extreme ly poor in Alu repeats (4.1% of the total length). Both intervals contain a lmost the same amount of the LINE-type repeats L1 and L2 (20.3 and 21.24%, respectively), In the chromosomal region studied, 29 Alu repeats were found to belong to the evolutionary young subfamily Y, which is still capable of amplifying. A considerable proportion of repeats of this type with similar nucleotide sequences may contribute to the recombinational activity of the chromosomal region 13q14.3, which is responsible for its rearrangements in some tumors in humans.