Cloning of an immunoglobulin variable region gene from mouse embryo.

A 4.8-kilobase DNA fragment carrying an immunoglobulin gene coding for a mouse lambda chain variable region (Vlambda gene) was enriched about 350-fold from a total endonuclease EcoRI digest of embryonic DNA by a combination of preparative agarose gel electrophoresis of double-stranded DNA and CsCl density gradient centrifugation of R-loops formed with a purified lambda chain mRNA. DNA fragments thus enriched for the immunoglobulin gene were inserted in vitro in the middle of the genome of the vector phage lambdagt Wam 403, Eam 100, Sam 100 by use of the EcoRI cohesive ends. Transfection of CaCl2-treated Escherichia coli 803 [rk-, mk- (lacking restriction and modification systems for K-12)] with such hybrid DNA and subsequent screening of about 4000 plaques by in situ hybridization with purified 125I-labeled lambda chain mRNA led to isolation of a clone that carries a Vlambda gene (lambdagtWES-Ig 13). Electron microscopy of R-loops confirmed the presence of sequences homologous to part of the lambda chain mRNA in its 5'-end.     

Reiteration frequency of immunoglobulin light chain genes: further evidence for somatic generation of antibody diversity.

Methods have been developed for preparing mouse immunoglobulin light chain mRNA of better than 90% purity. Hybridization of both lambda and kappa mRNAs to excess liver DNA yielded results compatible with gene reiteration frequencies of two to three. There was no evidence of hybridization of these highly purified mRNAs to reiterated DNA, and, in fact, the kinetics of hybridization were very similar to that of purified globin mRNA. Purified lambda mRNA from tumors producing structurally different lambda chains were used in competition hybridization experiments. An unlabeled lambda mRNA competed with another, labeled lambda mRNA to the same extent as homologous unlabeled lambda mRNA. That is, base sequence homology among lambda mRNAs is so high that any lambda mRNA should cross-hybridize with all germ line variable (Vlambda) genes at least for those V-regions which are represented among myelomas. From amino-acid sequence data, it is argued that there are probably more than 25 different lambda V regions. Hence it is concluded that the number of germ line genes is too small to account for the diversity of lambda chains. A similar conclusion is drawn for kappa chains.     

Immunoglobulin light chain variable (V) region genes influence clinical presentation and outcome in light chain-associated amyloidosis (AL)

Light chain-associated amyloidosis (AL) is a plasma cell dyscrasia in which the secreted monoclonal immunoglobulin (Ig) light chains form amyloid fibrils. There is considerable heterogeneity in clinical presentation, and prognosis of the disease relates to the severity of organ dysfunction induced by amyloid deposits. The mechanisms by which the amyloid fibrils are deposited as well as the predilection for specific organ sites have not been clearly elucidated. This study characterizes the repertoire of immunoglobulin light chain variable genes used by the clonal B cell in AL amyloid patients, and the association of light chain variable region (VL) genes with clinical presentation and outcome is assessed in 58 (32 lambda and 26 kappa) patients. A preferential use of VL germ-line genes was noted for both AL kappa and lambda patients. There was a significant correlation between the use of the Vlambda VI germ-line donor, 6a, and renal involvement as well as the Vlambda III gene, 3r, with soft-tissue AL. The use of a biased VL gene repertoire also correlated with clinical outcome, revealing important trends for predicting prognosis. The use of Vlambda II germ-line genes was associated with cardiac amyloidosis and affected survival adversely. The presence of multiple myeloma also correlated with a poor prognosis. The presence of renal disease, on the other hand, was associated with improved survival. Therefore, identification of the clonal VL gene in AL has important implications in determining clinical outcome.     

Cloning immunoglobulin gamma 2b chain gene of mouse: characterization and partial sequence determination.

DNA from newborn mice was digested with restriction endonuclease EcoRI, and a 6.6-kilobase fragment encoding immunoglobulin gamma 2b chain mRNA derived from MPC 11 myeloma was enriched about 100-fold by RPC-5 column chromatography and agarose gell electrophoresis. The 6.6-kilobase fragment was cloned with lambda gt WES.lambda B as EK2 vector. The cloned phage (lambda WES.IgH22) contained the constant region gene of the gamma 2b chain but not the variable region gene of MPC 11 mRNA. The constant region genes of the other gamma chains (i.e., gamma 1, gamma 2a, and gamma 3) were not present in lambda gt WES.IgH22 DNA. R-loop mapping indicates that the gamma 2b chain structural gene is divided into two parts (330 +/- 60 SD base pairs and 930 +/- 110 SD base pairs) by an intervening sequence (360 +/- 100 SD base pairs). The nucleotide sequence around the junction of the hinge region and CH2 domain was determined and shown to match the amino acid sequence of the initial part of the CH2 domain of the gamma 2b chain. The base sequence upstream from the junction, however, is unrelated to the amino acid sequence of the CH1 domain and the hinge region of all the gamma chains whose sequences have been determined. These results indicate that the gamma 2b chain gene is interrupted at the junction of the hinge region and CH2 domain by an intervening sequence. The existence of two more intervening sequences, one between the CH1 domain and the hinge region and the other between the CH2 and CH3 domains, is discussed.     

Immunoglobulin Vlambda light chain gene usage in patients with Sj?gren's syndrome.

OBJECTIVE: To determine whether patients with Sj?gren's syndrome (SS) have abnormalities in Ig Vlambda and Jlambda gene usage, differences in somatic hypermutation, defects in selection, or indications for perturbations of B cell maturation. METHODS: Individual peripheral B cells from SS patients were analyzed for their Vlambda gene usage by single-cell polymerase chain reaction amplification of genomic DNA and compared with those from normal controls. RESULTS: Molecular differences from controls in Vlambda-Jlambda recombination were identified that were reflected by findings in the nonproductive Vlambda repertoire of the patients, including enhanced rearrangement of Vlambda10A and Jlambda2/3 gene segments. In addition, a number of abnormalities in the productive repertoire were identified, indicating disordered selection. A greater usage of 4 Vlambda genes (2A2, 2B2, 2C, and 7A), representing 56% of all productive Vlambda rearrangements, was observed, suggesting positive selection of these genes. Overutilization of Jlambda2/3 and underutilization of Jlambda7 in both nonproductive and productive Vlambda rearrangements of SS patients compared with controls suggested decreased receptor editing in SS. The mutational frequency did not differ from that in controls, and positive selection of mutations into the productive V gene repertoire was found, similar to that in controls, although mutational targeting toward RGYW/WRCY motifs, typically found in controls, was not found in SS patients. CONCLUSION: Disturbed regulation of B cell maturation with abnormal selection, defects in editing Ig receptors, and abnormal mutational targeting may contribute to the emergence of autoimmunity in SS.     

Structure of genes for human growth hormone and chorionic somatomammotropin.

A 2.6-kilobase (kb) EcoRI restriction endonuclease fragment containing human growth hormone (hGH; somatotropin) gene sequences and a 2.8-kb EcoRI fragment containing human chorionic somatomammotropin (hCS; choriomammotropin) gene sequences have been identified by hybridization to cloned cDNA. Human DNA was cleaved with EcoRI and fractionated by preparative agarose gel electrophoresis; DNA in the size range 2--3 kb was ligated to lambda gt WES.lambda B DNA and viable recombinant bacteriophage were recovered by in vitro packaging. After infection of Escherichia coli and screening of phage plaques, single isolates of hGH and hCS gene sequences were obtained. Restriction endonuclease mapping showed that the hGH gene contains three intervening sequences interrupting the coding sequence. Partial DNA sequence analysis of the hGH gene, obtained by the chain termination method, confirmed the location of the intervening sequences and the identity of the fragment.     

Human cardiac myosin heavy chain genes. Isolation of a genomic DNA clone and its characterization and of a second unique clone also present in the human genome

A gene sequence coding for myosin heavy chain (MHC) of human cardiac muscle was isolated by screening a human genomic library with a 32P-labelled 1.1kb SacI restriction fragment from a previously characterized cDNA clone specifying the light meromyosin and 3' untranslated region of mRNA encoding rabbit cardiac alpha-MHC. The DNA of this human genomic clone (lambda HCMHC8) hybridized much more strongly than did other clones isolated under similar, low stringency conditions both to the rabbit cDNA probe and to mRNA isolated from rat cardiac, but not skeletal, muscle tissue. Probe made from a DNA restriction fragment of lambda HCMHC8 hybridized a single 31S band of human ventricular mRNA. This size is identical to that of cardiac MHC mRNA of other species. Heteroduplex analysis showed hybridization of lambda HCMHC8 with exon segments in a rabbit cardiac MHC genomic clone (lambda MHC alpha 12/1). It also showed that lambda HCMHC8 spanned 14 kb of DNA and contained exon segments estimated to code for two-thirds of a MHC including the carboxylic acid terminus. By rescreening the library under more stringent conditions, where only DNA sequences having strong homology to cardiac MHC genes would be expected to hybridize, clones having restriction maps overlapping lambda HCMHC8 were isolated together with a unique clone (lambda HCMHC9). DNA gel blot hybridization of human genomic DNA with lambda HCMHC8 probe at medium stringency gave a pattern of restriction fragments similar to the restriction map of lambda HCMHC8. A weaker set of bands also appeared which corresponded in pattern to the map of lambda HCMHC9.(ABSTRACT TRUNCATED AT 250 WORDS)     

Chromosomal locations of mouse immunoglobulin genes.

The chromosomal locations of the structural genes coding for the constant portions of mouse heavy (H) and light chain immunoglobulins were studied by molecular hybridization techniques. Complementary DNA probes containing the constant-region sequences of kappa and lambdaI light chain and alpha, gamma2b, and mu heavy chain mRNAs were annealed to a large excess of DNA from a series of eight mouse-human hybrid cell lines that are deficient for various mouse chromosomes. The lines were scored as positive when a high proportion of a probe annealed and negative when an insignificant proportion annealed. Some lines were clearly negative for H and lambda and clearly positive for kappa. Others were positive or intermediate for lambda, positive for kappa and negative for H. Still others, including a line that was selected for the absence of the mouse X chromosome, were positive for all immunoglobulin species. These results demonstrate that the Clambda, Ckappa, and CH genes are located on different autosomes in the mouse. In contrast, the three heavy-chain families exhibited consistently uniform hybridization results, suggesting that the genes for Calpha, Cgamma, and Cmu are located on the same chromosome. A comparison of karyotypic data with hybridization data has limited the possible locations of the Ig genes to only a few chromosomes.     

Clonal immunoglobulin light chain variable region germline gene use in AL amyloidosis: association with dominant amyloid-related organ involvement and survival after stem cell transplantation

AL (primary or immunoglobulin light chain) amyloidosis (AL) differs from myeloma per se in that tissue deposits of amyloid are found, typically in association with small numbers of clonal plasma cells producing lambda light chains, and also in that AL patients typically present with a predominantly dysfunctional organ-system. This constellation of features - fibrillar deposits comprised of light chains, lambda light chain predominance, and organ-system tropism and dysfunction - remains unexplained. Select patients with AL respond to haemopoietic stem cell transplantation (SCT) with clinical improvement and extended survival, particularly those who do not have cardiac involvement. In order to ascertain whether the organ-system tropism of AL was associated with immunoglublin light chain variable region (Ig VL) germline gene utilization, we attempted to clone, sequence and assign germline donors to the clonal Ig VL genes of 62 AL patients, all of whom were treated with SCT. We succeeded in 39 cases, identifying clonal AL genes derived from donors of the lambdaI (n = 10), lambdaII (n = 5), lambdaIII (n = 6), lambdaVI (n = 11) and KI (n = 7) subtypes. The majority of the donors (IGLV6S1, DPL5, DPL2, DPL23 and LFVK431) were genes that appear in the expressed repertoire <5% of the time, suggesting an intrinsic propensity to form amyloid under certain conditions. Patients whose clones derived from the lambdaVI IGLV6S1 donor uniformly presented with dominant renal involvement while those with other Vlambda or unknown donors often had dominant cardiac or other organ involvement, particularly patients whose clones derived from the lambdaI DPL2 donor. In addition, both early (<3 months) and overall post-SCT survival were significantly better in lambdaVI IGLV6S1 patients compared to patients with other Vlambda donors. These findings indicate that there are important associations in AL amyloidosis among Ig VL gene utilization, organ-system tropism and post-SCT survival.     

Immunoglobulin gene rearrangements in hairy cell leukemia

Studies of hairy cell leukemia have yielded conflicting data about the cell of origin in this disease. To investigate this issue, we have examined the state of immunoglobulin genes in the cells of 11 randomly selected spleens showing histologic involvement with hairy cell leukemia. DNA was extracted from splenic tissue samples and digested with restriction endonucleases. Following agarose gel electrophoresis and transfer to nitrocellulose filters or activated nylon membranes, splenic DNA was hybridized with radiolabeled DNA fragment probes specific for the constant regions of the immunoglobulin heavy chain and kappa and lambda light chain genes. Autoradiograms of the hybridized DNA in each case revealed rearrangements of a heavy chain gene and at least one light chain gene. In addition, immunophenotyping of cellular immunoglobulin polypeptides was carried out on frozen tissue sections from all but one case. In each case in which an immunoglobulin polypeptide could be detected, a rearrangement was present in the DNA of the corresponding immunoglobulin gene. These studies offer strong evidence for endogenous immunoglobulin synthesis in hairy cells and for the B lymphocytic character of this leukemia.     

Construction and propagation of a defective simian virus 40 genome bearing an operator from bacteriophage lambda.

A 2400 base pair DNA segment containing the leftward operator (OL) of phage lambda was covalently joined in vitro to a fragment of simian virus 40 (SV40) DNA harboring the SV40 replication origin. The recombinant molecule was propagated in the presence of helper wild-type SV40 DNA in monkey kidney cells and partially cloned by an infectious center procedure. After propagation in monkey cells and purification, the hybrid DNA could be distinguished from wild-type SV40 DNA by its shortened length (about 80% that of SV40), specific hybridization to denatured lambda DNA immobilized on filters, specific affinity for lambda repressor, and preservation of a large part (about 2300 base pairs) of the lambda immunity region as determined by restriction nuclease cleavage patterns and electron microscopic heteroduplex analysis. These results indicate that defective SV40 replicons can serve as vectors for propagating foreign DNA in mammalian cells.     

Molecular cloning of the mouse ouabain-resistance gene.

DNA prepared from ouabain-resistant mouse cells was able to transform ouabain-sensitive CV-1 cells to ouabain resistance after DNA-mediated gene transfer. The murine DNA fragment responsible for ouabain resistance was detected on the background of CV-1 DNA by virtue of a repetitive DNA sequence element that reacts positively with a mouse repeat DNA clone. CV-1 DNA is nonreactive with this probe. Southern analysis of several independently derived ouabain-resistant transformants indicates that the mouse ouaR gene is located on a 6.5-kilobase EcoRI restriction fragment. The 6.5-kilobase DNA fragment was initially isolated from a lambda phage library made from a ouabain-resistant secondary transformant and subsequently was subcloned in the plasmid vector pAT153. This plasmid was able to transform wild-type CV-1 cells to ouabain resistance at a frequency of about 10 cells per ng of DNA.     

Chronic lymphocytic leukemias utilizing the VH3-21 gene display highly restricted Vlambda2-14 gene use and homologous CDR3s: implicating recognition of a common antigen epitope

The immunoglobulin variable heavy chain (IgVH) gene mutation status is an important prognostic factor in chronic lymphocytic leukemia (CLL), since cases with mutated VH genes show significantly longer survival than unmutated cases. Recently, we reported a preferential use of the VH3-21 gene in mutated CLL and showed that mutated VH3-21 cases had an inferior overall survival compared with other mutated CLL. In order to further characterize this subset, we performed VH gene analysis in 265 CLL cases and identified 31 VH3-21 cases (11.7%); 21 cases had mutated and 10 cases unmutated VH genes. Regardless of VH gene mutation status, a poor overall survival was found in the VH3-21 cases with a median survival of 83 months. These survival data confirm that VH3-21 cases do not fit into the general prognostic grouping of mutated and unmutated CLL. A large fraction of VH3-21 cases also demonstrated unique features with shorter lengths of the third complementarity determining region (CDR3) and CDR3s with highly homologous amino acid sequences. Furthermore, the VH3-21 cases showed a striking dominance of lambda light chain expression, and analysis of the Iglambda gene rearrangements revealed highly restricted use of the Vlambda2-14/Jlambda3 genes in the majority of cases. Taken together, our new findings strengthen the suggestion that VH3-21-using cases comprise a new CLL entity, irrespective of VH gene mutation status, and implicate that a common antigen epitope, perhaps of pathogenic significance, is recognized by the highly homologous VH3-21/Vlambda2-14 Ig molecules expressed in individual tumors.     

人Midkine基因启动子片段的克隆

目的克隆人Midkine（MK）启动子基因2 335bp片段.方法自健康人血中提取人类基因组DNA作为模板,聚合酶链式反应（PCR）技术克隆人MK启动子基因2 335bp片段.琼脂糖凝胶电泳初步鉴定PCR产物,切取目的条带纯化并将其克隆入p GEM T载体中.选取阳性克隆进行DNA测序.结果电泳结果显示PCR产物包含有大小约为2 300 bp和1 400 bp的条带各1条;较大片段的测序结果显示,其与Genbank中的人MK启动子片段吻合.结论本研究成功克隆了人MK启动子基因2 335 bp片段.     

Structure of a third murine immunoglobulin lambda light chain variable region that is expressed in laboratory mice.

Recently, we reported evidence for the existence of an immunoglobulin lambda light chain (lambda x) whose variable region differs from those encoded by the known V lambda gene segments V lambda 1 and V lambda 2. Expression of lambda x was detected in some hybridomas elicited by treatment of a BALB/c mouse with rabbit anti-lambda 2 antibodies coupled to bacterial lipopolysaccharide [Sanchez, P. & Cazenave, P.-A. (1987) J. Exp. Med. 166, 265-270]. We constructed a cDNA clone from one hybridoma (B6) that expresses the lambda x chain and determined the complete nucleotide sequence. The deduced amino acid sequence of V lambda x is 30-33% identical with those encoded by V lambda 1 and V lambda 2 and by V kappa gene segments. The third hypervariable region of V lambda x is four codons longer than those of the other murine variable gene segments. The expression of lambda x requires a genomic rearrangement that juxtaposes the V lambda x gene with the J lambda 2-C lambda 2 joining-constant gene pair. Rabbit anti-V lambda x antibodies detected the lambda x light chain in the normal sera of all laboratory mice tested. Lambda x expression seems to be independent of lambda 1 expression, since both SJL and SJA strains, which are defective in lambda 1 production, express normal levels of lambda x chain.