Anker R, Caldwell J, Brokaw J, Pollok B A
Department of Microbiology and Immunology, Wake Forest University Medical Center, Winston-Salem, NC 27103.
Int J Cancer. 1989 May 15;43(5):930-5. doi: 10.1002/ijc.2910430534.
Immunoglobulin heavy- and light-chain mRNA of 11 Burkitt lymphoma (BL) cell lines (9 African and 2 American) were analyzed for various structural characteristics. In agreement with previous results at the protein level, all the BL cell lines express heavy-chain mRNA transcripts of the mu class. Surprisingly, a high mu s/mu m mRNA ratio was found in 2 IgM-producing BL cell lines (Raji and CCL85), that do not secrete immunoglobulin. Variable region gene use was also assessed in the cell lines: while 4 out of 7 endemic BL cell lines use VH genes that belong to the VH3 gene family, no clear bias in the expression of particular VH or VL gene families among this sampling of BL lines was found. Northern blot analysis of immunoglobulin transcripts in endemic BL cell lines did show that 2 such lines (AG876 and HTB62) expressed truncated heavy-chain transcripts; RNA sequence analysis of the VH region demonstrated different abnormal 5'-localized RNA splicing events for the 2 shortened mu transcripts. The light-chain mRNA in these 2 cell lines also showed structural abnormalities and, in the case of HTB62, 3 different kappa light-chain transcripts are produced (of elongated, native and truncated sizes). In vitro translation of mRNA from HTB62 showed mu and kappa chain proteins corresponding with the relative size for each message.
对11种伯基特淋巴瘤（BL）细胞系（9种非洲细胞系和2种美国细胞系）的免疫球蛋白重链和轻链mRNA进行了各种结构特征分析。与之前蛋白质水平的结果一致，所有BL细胞系均表达μ类重链mRNA转录本。令人惊讶的是，在2种不分泌免疫球蛋白的产生IgM的BL细胞系（拉吉细胞系和CCL85细胞系）中发现了高μs/μm mRNA比率。还对这些细胞系中的可变区基因使用情况进行了评估：虽然7种地方性BL细胞系中有4种使用属于VH3基因家族的VH基因，但在该BL细胞系样本中未发现特定VH或VL基因家族表达的明显偏向性。对地方性BL细胞系中免疫球蛋白转录本的Northern印迹分析确实表明，2个这样的细胞系（AG876和HTB62）表达截短的重链转录本；VH区域的RNA序列分析表明，这2种缩短的μ转录本存在不同的异常5'定位RNA剪接事件。这2个细胞系中的轻链mRNA也显示出结构异常，就HTB62细胞系而言，产生了3种不同大小（延长、天然和截短）的κ轻链转录本。对HTB62细胞系mRNA的体外翻译显示，μ链和κ链蛋白的大小与各自的mRNA相对应。
