IMMUNOGLOBULIN VARIABLE REGION USAGE IN CHRONIC LYMPHATIC LEUKEMIA

在这项资助的前两年，我们描述了结构， 免疫球蛋白重链可变区（VH）的重排和转录 和恒定（CH）区段在B细胞慢性淋巴细胞白血病（CLL）中。 我们最初的假设是在CLL中VHV家族的偏倚使用 亲属关系被发现适用于一般人群。 大约30%的 CLL仅重排和体细胞突变三种VHV中的一种（VH251）， 基因. VH251的生殖系转录本在CLL中以高频率出现 所有细胞 未观察到VHV和VL使用的相关性。 我们有 确定了CLL DNA中跨Cmu-C δ基因座的整个序列， 已经分析了B细胞发育阶段的转录。 我们发现 意想不到的高水平的分泌形式的δ mRNA（δ）， 可能源自一种独特有效的重组机制， cmu. 最后，在分析两个儿童攻击性CLL病例时，我们 发现一种常见的染色体易位[t（2，14）（2p13; 14q32）]， 在未表征区域中彼此40 bp内的断点 着丝粒到C κ。 该2p13区域被低甲基化并转录 在肿瘤和CD5阳性B细胞中。 另外两个儿科肿瘤显示 2p13染色体内缺失，位于t（2; 14）端粒的约25 kbp处 休息. 我们希望在下一个拨款期内， 四个具体目标：（1）测序重组VHV基因， 一组CLL和CD 5+和CD 5-正常B细胞，以确定是否 选择可以在转换过程中起作用。 (2)分析 VHV生殖系转录本结构和阶段特异性表达 正常细胞和恶性细胞与 VHV基因 (3)确定增加三角洲水平的机制， 正常和恶性B细胞。 (4)研究潜在的发展 显示缺失的2p13染色体基因座的调节， CLL中的易位。

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.