Goldrick M M, Boyd R T, Ponath P D, Lou S Y, Gottlieb P D
J Exp Med. 1985 Aug 1;162(2):713-28. doi: 10.1084/jem.162.2.713.
Previous studies (21) have shown that two mouse kappa light (L) chain variable (V) region polymorphisms, the IB-peptide and Efla markers, reflect expression of a characteristic group of V kappa regions, called V kappa Ser, by some inbred strains and not others. Expression of V kappa Ser is controlled by a locus on chromosome 6, the chromosome that contains the kappa locus. To further characterize this V kappa group and begin to analyze the basis for its strain-specific expression, full-length complementary DNA (cDNA) copies were produced of L chain mRNA from the M75 myeloma that had been induced in the C.C58 strain of mice, and which produces a V kappa Ser L chain. The C.C58 strain is congenic with BALB/cAn, differing in the region of chromosome 6 that controls expression of the V kappa polymorphisms and the Lyt-2 and Lyt-3 T cell alloantigens. The complete nucleotide sequence of this cloned cDNA was determined and compared with the nucleotide sequences the most closely related BALB/c myeloma L chains known. Results indicated significant differences throughout the variable region, but particularly toward the 5' portion of the sequence. A probe corresponding to 200 bp of the 5' end of the cloned V kappa Ser cDNA was used in Southern hybridizations of restriction digests of liver DNA from a number of inbred, recombinant, and recombinant inbred strains. Under stringent hybridization conditions, one strongly-hybridizing fragment was observed in Bam HI, Hind III, and Eco RI digests, and based on the size of the fragments, strains could be organized into two groups. The presence of strongly hybridizing Bam HI, Hind III, and Eco RI fragments of 3.2, 2.8, and 2.1 kb, respectively, was found to correlate completely with expression by the strain of the IB-peptide and Efla markers. All nonexpressor strains yielded hybridizing fragments of 7.8, 8.4, and 2.8 kb, respectively. Possible explanations for strain-specific expression of V kappa Ser-associated phenotypic markers are discussed.
先前的研究（21）表明，两种小鼠κ轻链（L）可变（V）区多态性，即IB肽和Efla标记，反映了一组称为VκSer的特征性Vκ区在某些近交系中的表达情况，而在其他近交系中则不表达。VκSer的表达受6号染色体上一个位点的控制，该染色体包含κ基因座。为了进一步表征这个Vκ组并开始分析其品系特异性表达的基础，我们制备了来自M75骨髓瘤的L链mRNA的全长互补DNA（cDNA）拷贝，M75骨髓瘤是在C.C58品系小鼠中诱导产生的，它产生VκSer L链。C.C58品系与BALB/cAn同源，在6号染色体上控制Vκ多态性以及Lyt-2和Lyt-3 T细胞同种异体抗原表达的区域存在差异。测定了该克隆cDNA的完整核苷酸序列，并与已知的最密切相关的BALB/c骨髓瘤L链的核苷酸序列进行了比较。结果表明，在整个可变区都存在显著差异，尤其是在序列的5'端部分。用对应于克隆的VκSer cDNA 5'端200 bp的探针，对多个近交系、重组系和重组近交系小鼠肝脏DNA的限制性酶切片段进行Southern杂交。在严格的杂交条件下，在Bam HI、Hind III和Eco RI酶切片段中观察到一个强杂交片段，根据片段大小，品系可分为两组。发现分别存在3.2、2.8和2.1 kb的强杂交Bam HI、Hind III和Eco RI片段，与品系中IB肽和Efla标记的表达完全相关。所有非表达品系分别产生7.8、8.4和2.8 kb的杂交片段。文中讨论了VκSer相关表型标记品系特异性表达的可能解释。
