CELLULAR AND STRUCTURAL STUDIES OF MYELOMA MUTANTS

我的研究项目主要集中在DNA序列上 抗体基因重排事件，特别是重(H)链类 开关重组。通过对小鼠骨髓瘤MPC11的检查 细胞系及其变种，我们观察到了另一种重组 事件，不限于抗体基因，即不等姐妹染色质 交易所(USCE)。我们建议生成一种通用基板，用于 分析重组序列，包括那些中介H链的序列 班级转换和涉及USCE的那些。MPCll USCE活动 涉及TC和TG二核苷酸片段，每一条都能够 TC采用了一种不寻常的DNA构象，一种三链结构， 对于TG，左撇子DNA。我们建议研究DNA的构象 甘油三酯和甘油三酯二核酸区并列在USCE的位置 事件。我们已经开始分析MPC11变异细胞，这些细胞显然 有趣的是，它们不稳定，因为它们显示出两者的重新排列 恒定和可变区域，意味着一定程度上独立于反馈 监管。对一种变种的初步研究导致了观察到 位于钙基因3‘端的序列在几个 骨髓瘤和杂交瘤细胞系。我们提议用实验来研究 这些3‘β重排的功能和结构意义 活动对免疫球蛋白群组的组织和表达具有重要意义。我们的龙 学期目标是了解Ig重排可能是如何模式化的 以及在各种不同的 恶性肿瘤是可以避免的。

My research program has focused on the DNA sequences that mediate antibody gene rearrangement events, especially heavy (H) chain class switch recombination. Through examination of the MPCll mouse myeloma cell line and its variants, we have observed another recombination event, not confined to antibody genes, namely, unequal sister chroinatid exchange (USCE). We propose to generate a universal substrate for assaying recombinogenic sequences, including those that mediate H chain class switching and those involved in USCE. The MPCll USCE event involves TC and TG dinucleotide tracts, each of which is capable of adopting an unusual DNA conformation for TC, a triplestranded structure, and for TG, left-handed DNA. We propose to examine the DNA conformation of the juxtaposed TC and TG dinucleotide tracts at the site of the USCE event. We have begun analysis of MPCll variant cells that are apparently and interestingly unstable in that they show rearrangements of both constant and Variable regions, implying some independence from feedback regulation. Initial study of one variant has led to the observation that sequences lying 3' of the Ca gene undergo rearrangements in several myeloma and hybridoma cell lines. We propose experiments to investigate the functional and structural significance of these 3'beta rearrangement events to the organization and expression of the Ig cluster. Our long term goal is to understand how patterned Ig rearrangements may be governed and how promiscuous rearrangements underlying various malignancies may be avoided.