IMMUNOGLOBULIN VARIABLE REGION USAGE IN CHRONIC LYMPHATIC LEUKEMIA

在这笔赠款的头两年里，我们描述了结构， 免疫球蛋白重链可变区的重排和转录 B细胞慢性淋巴细胞白血病(CLL)的恒定(CH)节段。 我们最初的假设是在CLL中偏向使用VHV家族 研究发现，亲缘关系适用于一般人群。约占总数的30% CLL仅对三种VHV中的一种(VH2 51)进行重排和体细胞突变 基因。VH2 51的胚系转录本在CLL中出现的频率很高 和所有的细胞。未发现VHV和VL使用率之间的相关性。我们有 确定了CLL DNA中CMU-C Delta基因座的整个序列 分析了B细胞发育阶段的转录。我们发现 出人意料的高水平分泌形式的Delta mRNA(Deltas) 可以从唯一有效的重组机制中派生出来删除 CMU。最后，在分析两个儿童侵袭性CLL的病例中，我们 发现一种常见的染色体易位[t(2，14)(2p13；14q32)] 在一个未确定特征的区域中，40个BP以内的断点 着丝粒到Ckappa。这个2p13区域是低甲基化和转录的 在肿瘤和CD5阳性的B细胞中。另外两个儿科肿瘤显示 T(2；14)染色体内2p13缺失，约25kbp端粒 休息一下。 我们寻求在下一个资金期将这些意见延长到 四个特异目的：(1)对重排的VHV基因进行序列测定 CLL和CD5+和CD5-正常B细胞的面板来确定 选择可能在转变过程中起作用。(2)分析 VHV生殖系转录本的结构和阶段特异性表达 正常细胞和恶性细胞与偏向重排相关 VHV基因。(3)确定中增量水平增加的机制 正常和恶性B细胞。(四)研究发展潜力 2p13染色体基因缺失和缺失的调节 慢性淋巴细胞性白血病易位。

During the first two years of this grant we characterize structure, rearrangement and transcription of immunoglobulin heavy chain variable (VH) and constant (CH) segments in B cell chronic lymphocytic leukemia (CLL). Our original hypothesis of biased usage of the VHV family within CLL kindred was found to apply to the population at large. About 30% of all CLLs rearrange and somatically mutate only one (VH251) of the three VHV genes. Germline transcripts of VH251 are noted at high frequency in CLL and ALL cells. No correlation of VHV and VL usage was noted. We have determined the entire sequence across the Cmu-Cdelta locus in CLL DNA and have analyzed transcription at stages of B cell development. We found unexpectedly high levels of the secreted form of delta mRNA (deltas) which may derive from a uniquely efficient recombinational mechanism to delete Cmu. Finally, in analyzing two cases of aggressive CLL in children, we found a common chromosomal translocation [t(2,14)(2p13;14q32)] with breakpoints within 40 bp of one another in an uncharacterized region centromeric to Ckappa. This 2p13 region is hypomethylated and transcribed in the tumors and in CD5-positive B cells. Two other pediatric tumors show a 2p13 intrachromosomal deletion about 25 kbp telomeric to the t(2;14) breaks. We seek to extend these observations in the next funding period through four specific aims: (1) Sequence the rearranged VHV genes of an extended panel of CLLs and of CD5+ and CD5- normal B cells to determine whether selection may be operative in the transformation process. (2) Analyze the structure and stage-specific expression of VHV germline transcripts in normal and malignant cells as correlated with the biased rearrangement of the VHV genes. (3) Determine the mechanism for increased deltas levels in normal and malignant B cells. (4) Study the potential developmental regulation of the 2p13 chromosomal locus that shows deletion and translocation in CLL.