Kuehl W M, Kaplan B A, Scharff M D
Cell. 1975 Jun;5(2):139-47. doi: 10.1016/0092-8674(75)90022-7.
Cultured MPC 11 mouse myeloma cells synthesize not only gamma2b heavy and kappa light chains but also a carboxyl terminal (constant region) fragment of kappa light chain. In vitro translational analysis of total cytoplasmic and microsomal RNA indicates that these cells contain RNA which directs synthesis of both a light chain precursor and a light chain fragment precursor. Variant clones which do not synthesize either heavy or light chains continue to synthesize the light chain fragment. One such "nonproducing" variant was studied in detail. It does not contain translatable mRNA for the intact light chain but does contain RNA which is translated into the light chain fragment precursor. Nucleic acid hybridization analysis with a cDNA probe specific for the constant region of kappa light chains revealed that microsomal RNA from the wild-type cell contains both 14S and a 10S species of kappa specific RNA, whereas the variant contains only the 10S species. Translational analysis of these same RNAs indicates that the 14S species codes for the light chain precursor, while the 10S RNA codes for the light chain fragment precursor.
培养的MPC 11小鼠骨髓瘤细胞不仅能合成γ2b重链和κ轻链，还能合成κ轻链的羧基末端（恒定区）片段。对总细胞质和微粒体RNA的体外翻译分析表明，这些细胞含有指导轻链前体和轻链片段前体合成的RNA。不合成重链或轻链的变异克隆继续合成轻链片段。对其中一个这样的“不产生”变异体进行了详细研究。它不含有完整轻链的可翻译mRNA，但确实含有可被翻译成轻链片段前体的RNA。用针对κ轻链恒定区的cDNA探针进行核酸杂交分析表明，野生型细胞的微粒体RNA含有14S和10S两种κ特异性RNA，而变异体只含有10S种类。对这些相同RNA的翻译分析表明，14S种类编码轻链前体，而10S RNA编码轻链片段前体。
