N-terminal sequence heterogeneity of guinea pig anti-DNP kappa chains.
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Amino Acid Sequence↗
Biomedical subjects
L Hood
Publications and source records attributed to L Hood.
Amino acid sequence restriction in rabbit antibody light chains.
Light chains were obtained from IgG rabbit antibodies to the group-specific carbohydrates of groups A and C streptococci. An analysis of the amino acid alternatives which exist at the first three positions of the N-terminus in both light-chain preparations shows a marked restriction in amino acid sequence heterogeneity when compared with preimmune light chains. Both of these related, but immunologically distinct, antigenic determinants select the same uncommon subpopulation of rabbit light chains.
Amino Acid Sequence↗
Immunologlobulin lambda chain structure: two genes, one polypeptide chain.
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Amino Acid Sequence↗
Genetic implications of common region sequence comparisons of lambda immunoglobulin chains differing at position 190.
The common regions of two lambda chains (amino acid residues 109 to 213) have been partially sequenced. These two human immunoglobulin chains have lysine at position 190, but are otherwise identical in their common-region sequence to four reported lambda chains that have arginine at position 190. The single amino acid interchange at position 190 may be explained either by an ambiguous codon at this position or by a gene duplication so recent that only a single mutational event has occured.
Amino Acid Sequence↗
Comparative analysis of the IgG heavy chain carbohydrate peptide.
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Amino Acids↗
Mechanism of antibody synthesis: size differences between mouse kappa chains.
Structural analysis of immunoglobulin light chains has been carried out in an attempt to elucidate the genetic mechanisms involved in antibody synthesis. Analysis of two mouse kappa-chain proteins is almost complete. The differences are localized in one-half of the molecules, and do not reflect the operation of any one mutational mechanism. The peculiar character of the differences is discussed with reference to various theories of antibody formation. The finding that the two proteins differ in size is incompatible with certain proposed theories.
Amino Acid Sequence↗
Pulsed field gel electrophoresis: studies of DNA migration made with the programmable, autonomously-controlled electrode electrophoresis system.
We have studied the migration of DNA in pulsed field agarose gels under a variety of electrophoresis conditions. We have made use of an instrument which can generate electric fields of any orientation, magnitude, or duration to compare different separation techniques for DNA molecules of from 1 to several thousand kilobase pairs. We discuss the capabilities of the system and present results of gel runs in which electrophoresis conditions were changed individually or in combination. The mobility of DNA in pulsed field gels is shown to reflect a number of interdependent physical parameters.
Autoanalysis↗
Model genomes: the benefits of analysing homologous human and mouse sequences.
The human genome initiative has provided the motivating force for launching sequencing projects suitable for testing various DNA-sequencing strategies, as well as motivating the development of mapping and sequencing technologies. In addition to projects targeting selected regions of the human genome, other projects are based on model organisms such as yeast, nematode and mouse. The sequencing of homologous regions of human and mouse genomes is a new approach to genome analysis, and is providing insights into gene evolution, function and regulation which could not be determined so easily from the analysis of just one species.
Animals↗
Molecular genetics of anti-carbohydrate antibodies.
Antibodies directed against carbohydrate determinants provide useful model systems for understanding the structure and organisation of antibody genes and the generation of antibody diversity. We have used three such systems, PC, DEX and GAC, and have studied the heavy chains and VH gene segments of each. In two of these systems, PC and GAC, much of the diversity in heavy-chain protein sequences results from somatic mutation events superimposed on expression of a single VH gene. In the DEX system, it appears that germ-line sequence diversity may be an important contributor to the variability in heavy-chain sequence. Detailed structural analyses of this type will ultimately provide a complete picture of the mechanisms which underlie effective humoral immunity.
Animals↗
Student and preceptor perceptions of factors in a successful learning partnership.
Thirty-two registered nurse preceptors and 42 senior undergraduate nursing students completed a survey ranking factors related to both participants in the clinical learning partnership. Mann-Whitney U-Wilcoxon Rank Sum W tests showed statistically significant differences in the ranking of four factors (the ability to give and receive criticism, knowledge of the preceptoring process, clinical competence, and compatibility) that contribute to successful learning partnerships. Nurse educators and professional nurses should acknowledge these perceptual differences and include these in student and preceptor orientation programs to promote a positive teaching and learning partnership.
Education, Nursing↗
Rearrangement of genetic information may produce immunoglobulin diversity.
The nearly complete amino-acid sequences of 22 closely related immunoglobulin kappa variable (Vkappa) regions from the inbred NZB mouse are presented. This group of Vkappa regions is encoded by at least six germline Vkappa genes. These data also suggest that the mouse kappa gene is divided into three segments termed V or variable (residues 1 to 98 or 99), J or joining (residues 99 or 100 to 112) and C or constant (residues 113--219). Tonegawa et la. have recently described a similar J segment for mouse lambda chains. Inbred mice contain multiple Vkappa and Jkappa gene segments. Therefore, different combinations of V and J gene segments may be joined at the DNA level during the differentiation of individual lymphocytes to contribute to antibody diversity.
Amino Acid Sequence↗
Expression of I-Ak class II genes in mouse L cells after DNA-mediated gene transfer.
The I-region of the mouse H-2 complex encodes I-region-associated or Ia antigens which are involved in lymphocyte interactions and in the regulation of immune responsiveness. Two Ia antigens, termed I-A and I-E, have been identified; both are cell-surface integral membrane glycoproteins which consist of two noncovalently linked polypeptide chains designated alpha (molecular weight (MW) approximately 34,000) and beta(approximately 28,000 MW). Their expression is restricted to B lymphocytes and to antigen-presenting cells such as macrophages. Inside the cell, these alpha beta dimers are associated noncovalently with a nonpolymorphic chain of 31,000 MW designated the invariant (Ii) chain. Cloning of 200 kilobases (kb) of the I-region from mice of the H-2d and H-2k haplotypes was accomplished recently in our laboratory, and the genes encoding the four polypeptide chains, A alpha, A beta, E alpha and E beta, were identified. We now describe the successful expression of I-Ak molecules in transfected mouse L cells.
Animals↗
A novel 6:10 chromosomal translocation in the murine plasmacytoma NS-1.
Specific chromosomal abnormalities are regularly associated with many murine and human malignancies. In particular, the majority of murine plasmacytomas and human Burkitt's lymphomas contain a characteristic translocation which results in the juxtaposition of a cellular oncogene, c-myc, with the immunoglobulin heavy-chain gene locus, and this rearranged c-myc directs the synthesis of qualitatively and quantitatively abnormal transcripts which may have an aetiological role in the development of the transformed state in lymphoid malignancies. Similarly, rearrangement and abnormal expression of c-myb (ref. 10) and c-mos (ref. 11) has been reported in other murine lymphoid tumours. Here we describe a novel 6:10 chromosomal translocation in the murine plasmacytoma cell line NS-1 which juxtaposes the immunoglobulin Ck gene with a single-copy sequence of unknown function. The NS-1 plasmacytoma is a frequently used fusion partner in hybridoma production and is known to contain a rearranged c-myc gene and a genetic element which transforms normal mouse fibroblasts in DNA-mediated transfection assays. We conclude that individual B-cell tumours may contain multiple chromosomal translocations perhaps relevant to oncogenesis.
Animals↗
A microchemical facility for the analysis and synthesis of genes and proteins.
A series of automated instruments that use state-of-the-art chemical methods has been developed for high-sensitivity protein sequencing, DNA synthesis and peptide synthesis. These instruments have been integrated into a centralized microchemical facility in order to promote their use for the study of a variety of biologically interesting problems. This facility has as one of its major functions the development of new chemistries and instrumentation for the structural analysis and synthesis of genes and proteins.
Amino Acid Sequence↗
The structure, rearrangement and expression of D beta gene segments of the murine T-cell antigen receptor.
It has been postulated that the variable region of the beta-polypeptide of the murine T-cell antigen receptor is encoded by three distinct germ-line gene segments--variable (V beta), diversity (D beta) and joining (J beta)--that are rearranged to generate a V beta gene. Germ-line V beta and J beta gene segments have been isolated previously. Here we report the isolation and characterization of two germ-line D beta gene segments that have recognition signals for DNA rearrangement strikingly similar to those found in the three immunoglobulin gene families and in V beta and J beta gene segments. The D beta and J beta segments can join in the absence of V beta gene segment rearrangement and these rearranged sequences are transcribed in some T cells.
Animals↗
Identification of a diversity segment of human T-cell receptor beta-chain, and comparison with the analogous murine element.
The humoral immune system antigen-binding proteins (immunoglobulins) are disulphide-linked heterodimers of light and heavy chains. The gene for the variable region which determines antigen specificity is assembled when one member from each of the dispersed clusters of variable (V) gene segments, diversity (D) elements (for the heavy chains only) and joining (J) segments rearrange and fuse during B-cell development (reviewed in ref. 1). Short recognition sequences adjacent to these elements appear to be involved in the recombination process. The cellular immune system antigen recognition proteins are receptors on the surface of T cells, which are composed of disulphide-linked alpha-chains and beta-chains, each of which has a variable and constant region. Recently, cDNA clones of the beta-chain mRNA have been isolated; the genomic arrangement is very similar to immunoglobulin genes with multiple V beta genes, and two clusters of J beta segments, each of which is upstream from a constant-region gene segment. The V beta and J beta segments have adjacent recombinational recognition sequences like the immunoglobulin elements. However, approximately 10 nucleotides of the cDNA clones between the V beta and J beta regions were not present in the corresponding genomic elements and may have been due to intervening D beta segments. Here we describe a diversity element (D beta 1.1) in a region of high human-mouse homology about 650 bases 5' to the first J beta cluster. Two transcripts which include sequences upstream of D beta 1.1 are found in the human thymus. This region may have some other function besides providing the beta-chain with a diversity segment.
Amino Acid Sequence↗
Rearrangement and transcription of the beta-chain genes of the T-cell antigen receptor in different types of murine lymphocytes.
Rearrangements of T-cell receptor beta-chain genes are usually found on both chromosomal homologues, occurring by both deletional and non-deletional mechanisms. Two constant-region (C beta) genes have been identified previously and at least one is transcribed in every helper or cytotoxic T cell tested, but the choice of C beta gene expression is not correlated with the specialized functions of these T lymphocytes. By contrast, four of five suppressor T-cell hybridomas examined have deleted all known joining (J beta) gene segments and C beta genes and therefore may have antigen receptors encoded by different T-cell receptor gene families.
Animals↗
Genomic organization of the genes encoding mouse T-cell receptor alpha-chain.
The vertebrate immune system uses two kinds of antigen-specific receptors, the immunoglobulin molecules of B cells and the antigen receptors of T cells. T-cell receptors are formed by a combination of two different polypeptide chains, alpha and beta (refs 1-3). Three related gene families are expressed in T cells, those encoding the T-cell receptor, alpha and beta, and a third, gamma (refs 4-6), whose function is unknown. Each of these polypeptide chains can be divided into variable (V) and constant (C) regions. The V beta regions are encoded by V beta, diversity (D beta) and joining (J beta) gene segments that rearrange in the differentiating T cell to generate V beta genes. The V gamma regions are encoded by V gamma, J gamma and, possibly, D gamma gene segments. Studies of alpha complementary DNA clones suggest that alpha-polypeptides have V alpha and C alpha regions and are encoded by V alpha and J alpha gene segments and a C alpha gene. Elsewhere in this issue we demonstrate that 18 of 19 J alpha sequences examined are distinct, indicating that the J alpha gene segment repertoire is much larger than those of the immunoglobulin (4-5) or beta (14) gene families. Here we report the germline structures of one V alpha and six J alpha mouse gene segments and demonstrate that the structures of the V alpha and J alpha gene segments and the alpha-recognition sequences for DNA rearrangement are similar to those of their immunoglobulin and beta-chain counterparts. We also show that the J alpha gene-segment organization is strikingly different from that of the other immunoglobulin and rearranging T-cell gene families. Eighteen J alpha gene segments map over 60 kilobases (kb) of DNA 5' to the C alpha gene.
Amino Acid Sequence↗