Molecular Basis Of Human Disease Research Articles

Structural basis of G protein-coupled receptor function

The vast majority of extracellular signaling molecules, like hormones and neurotransmitters, interact with a class of membranous receptors characterized by a uniform molecular architecture of seven transmembrane α-helices linked by extra- and intracelluar peptide loops. In a reversible manner, binding of diverse agonists to heptahelical receptors leads to activation of a limited repertoire of heterotrimeric guanine nucleotide-binding proteins (G proteins) forwarding the signal to intracellular effectors such as enzymes and ion channels. Proper functioning of a G protein-coupled receptor is based on a complex interplay of structural determinants which are ultimately responsible for receptor folding, trafficking and transmembrane signaling. Applying novel biochemical and molecular biological methods interesting insights into receptor structure/function relationships became available. These studies have a significant impact on our understanding of the molecular basis of human diseases and may eventually lead to novel therapeutic strategies.

Development and application of herpes simplex virus vectors for human gene therapy.

Advances in understanding the molecular basis of human disease and the development of recombinant DNA methods is rapidly creating new means of disease diagnosis and treatment. Among the most revolutionary developments are technologies for transfer of therapeutic genes to the human body to treat both inherited and acquired disease. Gene therapy offers considerable promise for ameliorating otherwise intractable diseases such as immunopathological conditions, cancer, heart disease, and various metabolic and neurodegenerative syndromes. To fulfill this promise, more efficient and effective methods of gene delivery and appropriate gene expression must be developed. The lack of such techniques is currently the most significant impediment to the use of genetic therapy. Both viral and nonviral delivery systems are under development for specific gene-therapy applications. Herpes simplex virus (HSV) represents a novel vector system for gene delivery to the nervous system and other tissues. HSV is able to establish latency in nondividing neuronal cells in which genomes persist long-term but do not integrate or alter host-cell metabolism and that carry a promoter system uniquely capable of escaping repression that shuts off the expression of HSV-lytic genes during latency. This review examines efforts to create defective HSV vectors that are safe, noncytotoxic, and applicable to the treatment of cancer and diseases affecting peripheral nerves. Perhaps the most important use of HSV vectors will be for the treatment of neurodegenerative diseases of the brain, but additional studies are required to improve the design of promoters to ensure regulatable or effective levels of therapeutic gene expression.

Determination of the structures of respiratory enzyme complexes from mammalian mitochondria

Knowledge of the atomic resolution structures of the respiratory enzymes from mammalian mitochondria is likely to be essential for understanding the molecular basis of human diseases involving their dysfunction. Because they are membrane-bound multisubunit assemblies, the determination of their high resolution structures is a rather challenging undertaking. The greatest progress has been made with the ATP synthase. The structure of its catalytic domain, F 1-ATPase, has been solved by X-ray crystallography at 2.8 Å resolution. It supports a binding change mechanism of catalysis in intact ATP synthase in which the catalytic subunits are in different states of the catalytic cycle at any instant. Interconversion of the states may be achieved by rotation of an α-helical domain of the γ-subunit relative to the α 3 β 3 sub-assembly. The membrane domain of ATP synthase has been purified, and the stalk linking the catalytic and membrane domains has been reassembled in vitro from its constituent subunits. Considerable progress has also been made in analyzing the structure of bovine complex I. It has about 43 different subunits and 42 of them have been sequenced. All of the known prosthetic groups have been localized in its extrinsic membrane arm, which has been split away from the membrane subunits and purified. The next stage is to crystallize the domain and to solve its structure.

Automated DNA diagnostics using an ELISA-based oligonucleotide ligation assay.

DNA diagnostics, the detection of specific DNA sequences, will play an increasingly important role in medicine as the molecular basis of human disease is defined. Here, we demonstrate an automated, nonisotopic strategy for DNA diagnostics using amplification of target DNA segments by the polymerase chain reaction (PCR) and the discrimination of allelic sequence variants by a colorimetric oligonucleotide ligation assay (OLA). We have applied the automated PCR/OLA procedure to diagnosis of common genetic diseases, such as sickle cell anemia and cystic fibrosis (delta F508 mutation), and to genetic linkage mapping of gene segments in the human T-cell receptor beta-chain locus. The automated PCR/OLA strategy provides a rapid system for diagnosis of genetic, malignant, and infectious diseases as well as a powerful approach to genetic linkage mapping of chromosomes and forensic DNA typing.

Duncan's Diseases of Metabolism, ed 6. Volume 1, Genetics and Metabolism, Pp 770, with 330 illustrations; volume 2, Endocrinology and Nutrition, Pp 667, with 264 illustrations.

These two volumes give systematic and comprehensive coverage of metabolic, endocrine, and nutritional disorders. They will be particularly appreciated by perennial scholars of these conditions, ie, medical students, pediatric scientists, pediatricians caring for patients with complicated disorders, and perhaps by an occasional parent wanting to learn more about his child's disease. Volume 1, Section 1: This consists of chapters devoted to gene structure and function, the biologic basis of inborn errors of metabolism and molecular disease. Co-authored by both MDs and PhDs, these three chapters are of particular interest to those of us who did not graduate from medical school within the past few years (ie, most of us). Much new work is covered and the results synthesized in order to make intelligible the molecular basis of human disease. Volume 1, Section 2: Intermediary metabolism is introduced by a chapter on the interrelationships between carbohydrates, lipids, and proteins. This chapter

Zonal centrifuges and other separation systems.

This discussion has included only a partial list of the systems now under development at Oak Ridge as part of the feasibility studies for the Molecular Anatomy Program. It is evident that we are still in the "Robert Goddard" phase of this work. It may not be premature, however, to suggest several conclusions. Biomedical scientists are discouraged on discovering that developmental efforts cost more, by one or two orders of magnitude, than pure research. In part this is because the full cost of development is generally shown, while in pure research some of the costs may be hidden, or the funds supplied by several sources. Regardless of the reason, the fact remains that development is expensive, as is well understood in nuclear physics and space science. The role and mission of the large national laboratories, and the kinds of research that should be done in them, have been discussed by Weinberg (63). The studies described here were in part stimulated by his ideas. We have been unable to find an environment outside a large national laboratory where a program like the Molecular Anatomy Program could be undertaken at the present rate. It appears that programs which attempt to make use of the multidisciplinary approach characteristic of national laboratories should be carefully designed and should evolve experimentally. There is less chance of success when a program is an administrative invention than when it evolves from scientific invention and discovery. It has been pointed out (64) that most program decisions in science are secret decisions in the sense that the scientific community as a whole does not participate in them. If a choice is to be made at some future time between large-scale expenditures for exploring space, for developing new weapons systems, for constructing new accelerators, for designing large reactors, or for systematically developing methods to explore the molecular basis of human disease, then we will need sufficient information to evaluate each alternative fully, and the information should be generally available. It appears desirable, therefore, to allow the Molecular Anatomy Program to proceed to a point where the full range of its contributions and its inherent limitations may be seen. A rational choice may then be made.