Showing papers by "Laboratory of Molecular Biology published in 1980"
TL;DR: An approach to DNA sequencing using chain-terminating inhibitors (Sanger et al., 1977) combined with cloning of small fragments of DNA in a single-stranded DNA bacteriophage is described, determining the 2771-nucleotide sequence of the largest MboI restriction enzyme fragment from human mitochondrial DNA.
2,902 citations
TL;DR: A model for the involvement of short direct repeat sequences in the generation of deletions in the noncoding and coding regions of B-like globin genes during evolution is described.
1,097 citations
TL;DR: To determine how different amino acid sequences form similar protein structures, and how proteins adapt to mutations that change the volume of residues buried in their close-packed interiors, the atomic structures of nine different globins are analysed and compared.
697 citations
TL;DR: An 18-Å resolution map of the ‘gap junction’ has been obtained by electron microscopy and analysis of two different subunit configurations suggests how the connexon might regulate the passage of small molecules between cell interiors.
Abstract: An 18-A resolution map of the 'gap junction' has been obtained by electron microscopy. The protein oligomer in the junctional membranes, the 'connexon', is a cyclinder composed of six subunits which are titled around its axis. Analysis of two different subunit configurations suggests how the connexon might regulate the passage of small molecules between cell interiors.
647 citations
TL;DR: The structure of oxymyoglobin has been refined at 1·6 A resolution, using diffractometer data collected at −12 °C, and movements of the haem, iron, F helix and FG corner on oxygenation are similar to those found in the T-R state transition in haemoglobin, but are smaller in magnitude.
604 citations
TL;DR: The nongonadal cells in the male nematode Caenorhabditis elegans have been followed through maturation by Nomarski microscopy and this region has been reconstructed by serial section electron microscopy in order to identify the cell types that arise from known lineages.
562 citations
TL;DR: The role of cell-cell interaction in the postembryonic development of nongonadal tissues in the nematode Caenorhabditis elegans has been explored by selective cell ablation with a laser microbeam and examples have been found of induction and of regulation in cell lineage and fate.
514 citations
TL;DR: The present results strongly suggest that protein cross-linking may be essential for receptor-mediated endocytosis of some protein and polypeptide hormones.
Abstract: The receptor-mediated endocytosis of alpha 2-macroglobulin can be inhibited by a diverse group of chemical compounds all of which share the property of being inhibitors of one form of cellular transglutaminase. The present results strongly suggest that protein cross-linking may be essential for receptor-mediated endocytosis of some protein and polypeptide hormones.
513 citations
422 citations
TL;DR: Twenty-four mutants that alter the normally invariant post-embryonic cell lineages of the nematode Caenorhabditis elegans have been isolated and genetically characterized, suggesting that their phenotypes result from the complete absence of gene activity.
Abstract: Twenty-four mutants that alter the normally invariant post-embryonic cell lineages of the nematode Caenorhabditis elegans have been isolated and genetically characterized. In some of these mutants, cell divisions fail that occur in wild-type animals; in other mutants, cells divide that do not normally do so. The mutants differ in the specificities of their defects, so that it is possible to identify mutations that affect some cell lineages but not others. These mutants define 14 complementation groups, which have been mapped. The abnormal phenotype of most of the cell-lineage mutants results from a single recessive mutation; however, the excessive cell divisions characteristic of one strain, CB1322, require the presence of two unlinked recessive mutations. All 24 cell-lineage mutants display incomplete penetrance and/or variable expressivity. Three of the mutants are suppressed by pleiotropic suppressors believed to be specific for null alleles, suggesting that their phenotypes result from the complete absence of gene activity.
404 citations
TL;DR: This unique, short-lived, specialized organelle selectively delivers the products of receptor-mediated endocytosis to intracellular sites using alpha 2-macroglobulin as the ligand and electron microscopic cytochemical methods.
TL;DR: Using electron microscopic immunocytochemistry, the intracellular location of the src protein (p21) in cells transformed by the Harvey strain of Murine Sarcoma Virus is investigated, suggesting that the plasma membrane is a major site of action for transforming proteins.
TL;DR: The 6407 nucleotide-long sequence of bacteriophage M13 DNA has been determined using both the chemical degradation and chain-termination methods of DNA sequencing and appears to be only a single nucleotide shorter than fd DNA.
TL;DR: It is observed that myosins isolated from the two non-muscle sources, thymus cells and platelets, are assembled into filaments at physiological ionic strength and Mg-ATP concentrations, only when the 20,000-MW light chain is phosphorylated.
Abstract: The presence of actin and myosin in non-muscle cells suggests that they may be involved in a wide range of cellular contractile activities1. The generally accepted view2 is that interaction between actin and myosin in these cells3–5 and in vertebrate smooth muscle6,7, is regulated by the level of phosphorylation of the 20,000-molecular weight (MW) light chain. In the absence of calcium, this light chain is not phosphorylated and the myosin cannot interact with actin. Calcium activates a specific calmodulin-dependent kinase8–11 which phosphorylates the light chain, initiating actin–myosin interaction. Although most studies on the role of phosphorylation have concentrated on the regulation of actin-activated myosin Mg-ATPase activity, phosphorylation of the light chain also seems to control the assembly of smooth muscle myosin into filaments12,13. Using purified smooth muscle light chain kinase, we have confirmed this observation. We report here studies of myosins isolated from the two non-muscle sources, thymus cells and platelets. We observed that these myosins are assembled into filaments at physiological ionic strength and Mg-ATP concentrations, only when the 20,000-MW light chain is phosphorylated.
TL;DR: This work has found that the distance between successive DNase I cutting sites is 10.6 ± 0.1 bases for the DNA immobilized on three different surfaces, and identifies this value with the number of base pairs per turn of the DNA double helix in solution.
Abstract: The periodicity of DNA has been determined by binding short, stiff pieces of DNA to a flat surface and using DNase I to probe the accessibility of the phosphodiester bonds. We have found that the distance between successive DNase I cutting sites is 10.6 +/- 0.1 bases for the DNA immobilized on three different surfaces. We identify this value with the number of base pairs per turn of the DNA double helix in solution.
TL;DR: The results suggest that a specialized DNA sequence is not essential for the initiation of semiconservative DNA replication in the Xenopus embryo, nor is a specialized sequence essential forThe mechanism which prevents reinitiation on a molecule which has already replicated within a cell cycle.
TL;DR: From the nucleotide sequence of the gene, the complete amino acid sequence of human fibroblast interferon was deduced and the protein is 166 amino acids long and is preceded by a 21-amino acid signal sequence.
Abstract: Chimaeric plasmids containing double-stranded cDNA copies of mRNA induced in human fibroblasts by poly I · C were screened by an RNA selection method. A series of clones to which human fibroblast interferon mRNA selectively hybridized was identified. From the nucleotide sequence of the gene, the complete amino acid sequence of human fibroblast interferon was deduced. The protein is 166 amino acids long and is preceded by a 21-amino acid signal sequence.
TL;DR: It is proposed that the (H3)2 (H4)2 tetramer forms a dislocated disk which defines the central turn of DNA, while the two H2A–H2B dimers lie one on each face, each associated with about one half a turn.
Abstract: Image reconstruction to 22 A resolution of the histone octamer (H3)2(H4)2(H2A)2(H2B)2 shows it to have a 2-fold axis of symmetry, and the overall shape of the left-handed helical spool on which to wind about two turns of a flat superhelix of DNA in the nucleosome. From this structure and the results of various cross-linking studies, we have deduced the arrangement of the individual histones. We propose that the (H3)2(H4)2 tetramer forms a dislocated disk which defines the central turn of DNA, while the two H2A-H2B dimers lie one on each face, each associated with about one half a turn.
TL;DR: A clone of hybrid myelomas (NK2), secreting a mouse monoclonal antibody to human leukocyte interferon, has been isolated and, when covalently attached to a solid support and used as an immunoadsorbent, allowsInterferon purification of up to 5,000-fold in a single step.
Abstract: A clone of hybrid myelomas (NK2), secreting a mouse monoclonal antibody to human leukocyte interferon, has been isolated. The antibody neutralizes the antiviral activity of the interferon and, when covalently attached to a solid support and used as an immunoadsorbent, allows interferon purification of up to 5,000-fold in a single step.
TL;DR: In the small nematode, Caenorhabditis elegans, mutants with a disorganized myofilament lattice structure have been identified by polarized light and electron microscopy and phenotypes are described for the mutants from the 9 complementation groups not previously reported on.
TL;DR: The refined structure of human carbonmonoxy haemoglobin is, as expected, generally similar to that of horse methaemoglobin and a detailed comparison of the structures of the deoxy and liganded forms from the same species is now possible.
TL;DR: Rat ventricular myosin contains two isoenzymes which can be separated by polyacrylamide gel electrophoresis in the presence of pyrophosphate buffers, and these phenotypes differ in their kinetic properties.
TL;DR: A DNA copy of the gene coding for the influenza A/Aichi/2/68 haemagglutinin protein was cloned in the plasmid pBR322 and the complete nucleotide sequence determined and documents further at the molecular level the two independent modes of antigenic variation of the virus—drift and shift.
Abstract: A DNA copy of the gene coding for the influenza A/Aichi/2/68 haemagglutinin protein was cloned in the plasmid pBR322 and the complete nucleotide sequence determined. Comparison of this primary structure and the deduced amino acid sequence with the haemagglutinin gene and protein of strains belonging to the same (H3) subtype and to different subtypes, of both human (H2) and avian (Hav1) origin, documents further at the molecular level the two independent modes of antigenic variation of the virus--drift and shift.
TL;DR: Electric dichroism is used to investigate chromatin fragments isolated from chicken erythrocytes and gives a quantitative description of the DNA conformation in the higher order structure of chromatin.
TL;DR: Specific initiation of transcription of Rous sarcoma virus by RNA polymerase II was obtained in a cell-free system using cloned RSV DNA as template, indicating that the basic information necessary for RSV transcription lies within the viral genome.
TL;DR: Nucleoplasmin interacts with histones in vitro in such a way that histones no longer adhere to negatively charged surfaces, and this rate is sufficient to account for the rate of nucleosome assembly required during the early development of Xenopus embryos.
TL;DR: The isolation from chick embryo brain of an actin depolymerizing protein with a polypeptide MI 19 000 is described, distinct from profilin in its isoelectric point and in its ability to disassemble actin filaments.
TL;DR: The jump in sedimentation observed between ionic strengths 45 and 55 m m, together with the effect of cross-linking, suggests the co-operative stabilization of this structure at higher ionic strength, and is compatible with a continuous pattern of condensation, such as a helix of nucleosomes.
TL;DR: The complete sequence of a hemagglutinin (HA) gene of a recent human influenza A strain, A/Victoria/3/75, is 1768 nucleotides long and contains the information for 567 amino acids as mentioned in this paper.
TL;DR: The results imply that the ancestral gene for collagen arose by multiple duplications of a single genetic unit containing a 54 bp condig segment.