Perry R P, Kelley D E, Coleclough C, Kearney J F
Proc Natl Acad Sci U S A. 1981 Jan;78(1):247-51. doi: 10.1073/pnas.78.1.247.
The organization and expression of immunoglobulin genes were studied in a series of six hybridomas derived from the fusion of a nonproducing myeloma cell with cells from mouse fetal liver. These hybridomas, which exhibit several phenotypic characteristics of immature B lymphocytes, all have productively rearranged mu heavy chain genes and produce both the membrane and secreted forms of mu mRNA in a ratio of about 1:10. Significantly, none of the hybridomas has an unrearranged (germ line) allelic mu gene. Examination of the kappa light chain genes revealed that all six of the hybridomas contain unrearranged kappa loci and produce 8.4-kilobase transcripts containing kappa constant region sequences. None of the five hybridomas that exhibit a mu-only phenotype contains a rearranged kappa gene other than that derived from the myeloma parent. One hybridoma, which actively secretes kappa immunoglobulin, contains a rearranged kappa gene of fetal liver origin and synthesizes a distinctive kappa mRNA precursor in addition to the 8.4-kilobase transcript. These results demonstrate that rearrangement of heavy chain immunoglobulin genes normally occurs prior to that of light chain genes and further indicate that the transcriptional competence of the kappa constant region locus is established prior to the time of its rearrangement.
对一系列六个杂交瘤进行了免疫球蛋白基因的组织和表达研究，这些杂交瘤源自非分泌性骨髓瘤细胞与小鼠胎肝细胞的融合。这些杂交瘤表现出未成熟B淋巴细胞的几种表型特征，均具有重排成功的μ重链基因，并以约1:10的比例产生膜形式和分泌形式的μmRNA。值得注意的是，所有杂交瘤均没有未重排（种系）的等位基因μ基因。对κ轻链基因的检测表明，所有六个杂交瘤均含有未重排的κ基因座，并产生含有κ恒定区序列的8.4千碱基转录本。表现出仅μ表型的五个杂交瘤中，除了源自骨髓瘤亲本的κ基因外，均不含有重排的κ基因。一个活跃分泌κ免疫球蛋白的杂交瘤，含有源自胎肝的重排κ基因，除了8.4千碱基转录本外，还合成一种独特的κmRNA前体。这些结果表明，重链免疫球蛋白基因的重排通常发生在轻链基因重排之前，进一步表明κ恒定区基因座的转录能力在其重排之前就已确立。
