Chick embryo poly (rA:dT)-dependent DNA polymerase.
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Journal Article↗
Biomedical subjects
F Rougeon
Publications and source records attributed to F Rougeon.
Mutation of immunoglobulin J chi splice sites does not affect the rearrangement frequency of J chi segments.
The rabbit b9 kappa 1 locus contains 5 joining (J chi) gene segments, only two of which, J chi 1 and J chi 2, are utilized in assembly of a complete variable region gene (as shown by Akimenko, M.-A., Mariamé, B. and Rougeon, F. (1986) Proc. natl. Acad. Sci. (Wash.), 83, 5180-5183). J chi 4 and J chi 5 do not rearrange because of deficient recombination signal sequences. The J chi 3 gene segment is also not rearranged and has a non-functional splice site. In view of the proposed relationship between transcription and rearrangement of immunoglobulin genes, we sought to determine whether splicing of the germline transcript is implicated in the rearrangement process. We addressed this question by introducing mutations in the splice sites of the J chi segments of an unrearranged kappa light chain immunoglobulin transgene. Rearrangement was analysed by polymerase chain reaction on transgenic spleen DNA. We observed that mutation of the splice sites had no effect on the utilization of the J chi gene segments, demonstrating that there is no relationship between splicing and rearrangement.
Animals↗
A V(D)J site-specific recombination model involving no compulsory double-stranded break formation at the coding segments.
Complete immunoglobulin and T-cell-receptor genes are assembled by site-specific recombination of separately encoded gene segments. We present a novel recombination model which accounts for all the characteristics of V(D)J recombination that have been described. The sequence of events proposed implies no formation of double-stranded breaks at the coding ends, ensuring continuity between the recombination partners during the reaction, and solves the problem of the ligation of extremities which have no complementarity. According to this recombination model, the formation of covalently sealed coding ends does not constitute a compulsory step in the recombination process.
Animals↗
Immunoglobulin kappa light-chain diversity in rabbit is based on the 3' length heterogeneity of germ-line variable genes.
Antibody diversity is generated by the combinatorial association of multiple distinct genetic segments (variable (V), joining (J) and diversity (D) light (L) and heavy (H) chains--VL, JL and VH, D, JH) and amplified somatically by three or four different mechanisms. The kappa system in mouse and human consists of 50-100 V kappa segments associated with a cluster of four or five functional J kappa segments, located 2.5 kilobases (kb) 5' to a single C kappa gene. The third hypervariable region (CDR3), which is part of the antibody combining site, is usually nine amino acids long in human and mouse kappa chains. It is encoded by the last seven codons of the V kappa segment and the first two of the J kappa segment, one codon sometimes being added or deleted between V and J by junctional variation. In the rabbit, the C kappa 1 gene which encodes the major isotype, is associated with a cluster of five J kappa segments, only one of which seems to be functional, thus significantly decreasing the combinatorial potential. However, amino acid sequence comparison has revealed extensive heterogeneity in the length of rabbit CDR3 , suggesting the existence of a D segment analogous to that in the heavy-chain system. We show here that rabbit V kappa genes have several additional nucleotides at their 3' ends. Thus, even with a single functional J kappa segment, high CDR3 diversity can be generated based on the length heterogeneity of V kappa germ-line segments and their greater length, which might leave scope for an increased junctional deletion.
Amino Acid Sequence↗
Structure of the mouse submaxillary gland renin precursor and a model for renin processing. Arthur C. Corcoran Memorial Lecture.
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Amino Acid Sequence↗
Nonproportional changes in plasma renin concentration, renal renin content, and rat renin messenger RNA.
The expression of the renin gene in rat kidneys was studied using mouse submaxillary gland renin complementary DNA. The length of rat renin messenger RNA (mRNA) was approximately 1600 nucleotides, similar to that of mouse submaxillary gland and kidney renin mRNA. Rat renin mRNA was quantified by a radiodensitometric complementary DNA hybridization assay. The effects of intense long-term stimulation and short-term inhibition of renin secretion on plasma renin concentration, renal renin concentration, and renin mRNA content were compared with those of controls. After 15 days of sodium depletion and captopril treatment, plasma renin concentration increased 46-fold, renal renin concentration only 1.5-fold, and renin mRNA content increased about threefold. Following a 1-hour infusion of angiotensin II in sodium-depleted and captopril-treated rats, plasma renin concentration decreased by 84% whereas no significant changes in either renal renin concentration or renin mRNA content were observed. These results show that sodium depletion and captopril treatment increase the level of renin gene transcription and renin biosynthesis. However, there are nonproportional changes in plasma renin levels, renal renin content, and its mRNA. These results suggest that newly synthesized renin is not stored in the kidney but is rapidly secreted into the blood. Short-term inhibition of plasma renin concentration by angiotensin II is most likely mediated by posttranslational mechanisms.
Angiotensin II↗
[Insertion of mouse kappa light chain immunoglobulin gene sequences into a bacterial plasmid].
The 14S mRNA from MOPC 173 tumour has been transcribed into cDNA by AMV DNA polymerase and converted into a double stranded form by Escherichia coli DNA polymerase I. After addition of oligo-dG tracts at the 3'-OH ends by calf thymus terminal transferase this DNA was hybridized to an E. coli plasmid (pCR1) to which oligo-dG tracts had been similarly added. Circular molecules resulting from GC base pairing have been used to transform C 600 E. coli cells and to confer kanamycine resistance. Several recombinants have been obtained containing the V+C regions and the C or V region alone. These recombinant molecules are being used to analyse the translocation of V and C genes and to purify V and C genes from DNA of germ line cells and of differentiated tumour.
Animals↗
Correlation between D region structure and antigen-binding specificity: evidences from the comparison of closely related immunoglobulin VH sequences.
A VH region gene is generated from three gene segments, VH, D and JH, separated on the germline chromosome and rearranged during differentiation to generate an active VH gene. The sequence and length variations of the D region are an important source of the antibody diversification. To investigate their role in the antigen recognition, VH sequences of three myeloma proteins (ABE48, UPC10 and MOPC173) having different antigen specificities and whose VH segments were expected to be highly homologous have been determined: cDNA clones containing the structural gene sequences for the three proteins have been constructed. The nucleotide sequences of the three VH regions have been determined. The deduced amino-acid sequences are compared to those of four other myeloma proteins (J539, X44, X24 and T601). The seven proteins have highly homologous VH segments. The comparison points out the correlation existing between the D-region structure and the antigen-binding specificity.
Amino Acid Sequence↗