1986 — 1999 |
Lomax, Margaret |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Tissue Specific Expression of Cytochrome C Oxidase @ University of Michigan Ann Arbor
Abstract 9405363 The enzyme complexes of the mitochondrial electron transport chain are unique. Each complex is composed of subunits encoded in two different genomes, the mitochondrial and the nuclear genomes. Cytochrome c oxidase (COX), the last enzyme complex in the chain provides an ideal model system in which to analyze both coordinate and tissue-specific transcriptional regulation of these essential respiratory genes. The long-term goal of this project is to understand the genetic regulatory mechanisms controlling both tissue-specific expression and developmental regulation of mammalian genes for the mitochondrial-encoded COX subunits. We will (1) define skeletal muscle-specific enhancer elements in the gene for COX subunit VIII-H by means of gene fusions with either the CAT or lacZ reporter genes (2) map the sites of DNA-protein interactions between nuclear proteins and tissue-specific enhancers in the COX8H gene by DNAse hypersensitivity, DNAse footprinting and electrophoretic mobility shift assays and determine the functional significance of these interactions by gene transactivation studies (3) physically map the bovine genes for the tissue-specific isoforms of COX subunit VIII and (4) nap the COX VIII isoform genes in the mouse by inter-specific hybrid back-crosses. %%% These studies will constitute the first comprehensive analysis of the transcriptional regulation of a class of genes, the tissue- specific respiratory genes, essential for respiratory function in contractile muscle. The results should provide insight into the genetic regulation of tissue-specific subunits of an essential multi-subunit enzyme complex involved in oxidative metabolism and provide tools to enable us to address the function of these isoforms in future studies. ***
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1989 — 1993 |
Lomax, Margaret |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Isolation and Characterization of Neural Crest Subpopulations @ University of Michigan Ann Arbor
The long-range objective of this project is to understand how subpopulations of neural crest cells differentiate into specific types of mature neurons during embryonic development. What genetic and other factors are at work? Dr. Barald and her coworkers have identified subpopulations of cells in the neural crest of chick and quail embryos with different biochemical properties. They have developed markers for these different subpopulations and techniques for separating these cell types while keeping them alive. They can now grow these subpopulations in culture and characterize their responses to a variety of regulatory factors as well as to examine the interaction of various genes important in cellular differentiation. By employing these methods, Dr. Barald's group will be able to answer the following questions: When does a neuronal population that is derived from the neural crest become determined, and therefore segregated from other cells in the crest lineage? Is the expression of the determined state plastic? Can it be modified by environmental cues in vivo or in vitro?
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0.915 |
1990 — 1994 |
Lomax, Margaret |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Tissue-Specific Expression of Cytochrome C Oxidase @ University of Michigan Ann Arbor
Mammalian cytochrome c oxidase (COX) consists of 13 subunits: three encoded in mitochondrial DNA and 10 in nuclear DNA. Long- term goals are to understand the regulation of this critically important enzyme complex through analysis of the genetic regulatory sequences controlling expression of COX nuclear genes. Short term goals include defining the cis-regulatory sequence elements (cis- elements) in the promoters of two COX genes: human COX5B (for a ubiquitous subunit VB), and bovine COX8H (for subunit VIII-heart). They will: (1) identify by DNA sequencing those cis-elements in the promoter of the COX5B gene known to be important for transcriptional control of other genes; (2) identify unique cis- elements important for transcriptional control of respiratory genes by functional analysis of the COX5B promoter through a) analysis of DNAseI hypersensitive sites, b) gene fusion experiments, and C) transient expression studies; (3) clone and sequence the promoter of the bovine COX8H gene to identify unique cis-elements important for tissue-specific expression. These studies on the cis- regulatory sequence elements controlling expression of nuclear genes for this unique enzyme complex will contribute to our understanding of the genetic regulatory signals involved in mitochondrial biogenesis and in tissue=specific expression of this important enzyme complex.*** //
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0.915 |
1994 — 1996 |
Lomax, Margaret I. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Molecular Evolution of Cytochrome C Oxidase @ University of Michigan At Ann Arbor
Cytochrome c oxidase (COX) comprises 13 subunits: 3 encoded in mitochondrial DNA (mtDNA), ten in the nucleus. Of the ten nuclear subunits, three (subunits VIa, VIIa, and VIII) have muscle-specific isoforms. The mitochondrial genes are known to evolve ten times faster than single copy nuclear genes in higher primates. Thus, COX provides an ideal system in which to determine how the increased mutation rate in mtDNA affects the mutation rate of the nuclear genes. The long-term goal of this project is tousle evolutionary (sequence) comparisons to assess the function of COX nuclear-coded subunits and the regulation of COX nuclear genes. By determining which regions of selected COX genes change only very slowly and thus appear evolutionarily constrained, and which regions have evolved rapidly, consistent with acquiring new or altered functions. The specific aims in pursuit of this goal are: Aim 1. To determine when in the evolution of higher primates the replacement substitutions observed in the human. COX4 gene occurred, and whether or not these changes are due to interaction with COX subunit II. Aim 2. To determine when in primate evolution the changes in the COX5B, COX7X and COX7AL gene occurred. Aim 3. To use the method of phylogenetic footprinting to identify conserved cis-regulatory sequence elements in the regulatory regions of both constitutively expressed and tissue- specific CO:X nuclear genes. Aim 4. To investigate the role of gene duplication on the evolution of the mammalian COX complex by determining the time of the gene duplication leading to the tissue-specific genes COX6AH COX7AH, and COX8H. Aim 5. To determine the rates of evolution of intron 1 of the COX6AH gene from coding sequence in the yeast homologue. Because COX is the terminal enzyme complex of the mitochondrial electron transport chain, it is critically important for oxidative metabolism in aerobic tissues. COX deficiency has been identified as the molecular defect in several types of mitochondrial myopathy and encephalomyopathy. Applying evolutionary approaches to define function and regulation of mammalian COX nuclear genes will provide insights into subunit function and tissue-specific gene regulation, particularly of the muscle-specific isoforms. These insights are critical to our understanding of this essential enzyme complex and will enable us eventually to design rational therapy for patients with these molecular defects.
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1996 — 2000 |
Lomax, Margaret I. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Molecular Analysis of Ear Development @ University of Michigan At Ann Arbor |
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1997 — 2001 |
Lomax, Margaret I. |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Molecular Genetics of Acoustic Trauma and Response to Trauma @ University of Michigan At Ann Arbor
noise biological effect; gene induction /repression; cochlea; auditory threshold shift; noise induced deafness; trauma; animal genetic material tag; in situ hybridization; polymerase chain reaction; laboratory rat; human genetic material tag;
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2000 — 2001 |
Lomax, Margaret I. |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Differential Gene Expression in Normal, Mutant and Aged @ University of Michigan At Ann Arbor
DESCRIPTION (Applicant's abstract): The overall scientific objectives of this proposal are to identify genes whose expression changes as a consequence of two types of sensorineural deafness in the mouse: age-related hearing loss in strain C57BL6/J, and congenital deafness in three deafness mouse mutants. These mutants are being studied at the University of Michigan by two of the co-investigators on this grant. Shaker-2 has been shown to carry mutations in the gene for an unconventional myosin, MyoXV, by Dr. Camper's group. Pirouette and spinner mutants have been mapped and the mutated genes are being identified by Dr. Kohrman's group. We propose to determine the broad effects on the transcriptional repertoire (transcriptome) of the inner ear due to single gene mutations that result in deafness in the mouse. This approach is based on two related hypotheses: (1) these mutations alter the normal developmental processes and homeostatic mechanisms that operate during maturation of the cochlea or in the adult organism, and (2), the alterations will be reflected in changes in the steady state transcript levels of genes that operate in the relevant developmental and homeostatic pathways. By using highly parallel methods to identify gene expression changes, we will begin to characterize the regulatory circuits that are affected directly or indirectly by the mutations, and which themselves may also play critical roles in normal inner ear development, homeostasis and function. Aims 1 and 2 propose to use currently available reagents and technique, such as gene arrays on nylon membranes, to examine gene expression changes in C57BL/6J, a mouse model of age-related hearing loss (Aim 1), and in the three mouse models of congenital deafness and vestibular dysfunction (Aim 2). The final two Aims address the feasibility of applying new and emerging techniques to increase the 'completeness' of the pool of profiled inner ear genes (Aim 3) through database comparisons and SAGE analysis, and the 'throughput' of expression profiling by developing DNA microarrays on glass slides containing genes expressed in the mouse inner ear (Aim 4). These studies should enhance our understanding of the molecular events of age-related hearing loss and congenital deafness and provide new reagents for assessing changes in gene expression in the ear.
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2005 — 2009 |
Lomax, Margaret I. |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Stress Pathways in the Aging Cochlea @ University of Michigan At Ann Arbor
The inducible stress response was first discovered as a "heat shock" response in Drosophila, but is now known to be a ubiquitous and highly conserved inducible mechanism to protect cells from various damaging physiological and environmental stresses. In mammals, this pathway is regulated through the activation of heat shock transcription factor 1 (Hsf 1), which induces heat shock proteins (Hsps). This project is based on evidence, both from published studies and from our preliminary data, that the inducible stress response decreases in aging animals. The overall hypothesis of this proposal is that the stress response system of the cochlea is similarly compromised in aged animals, making the sensory cells more vulnerable to stress and hence to cell death, leading to age-related hearing loss (ARHL). Studies in Aim 1 will use CBA mice with normal hearing throughout most of their lifespan to investigate the age-related decrease in the inducible stress response following two stresses: heat and noise. Aim 2 will investigate the hypothesis that the decrease in the stress response pathway with aging will be reflected in a decrease in the ability to recover from a noise exposure that causes only temporary hearing loss in wild-type mice. Studies in Aim 3 will test the hypothesis that eliminating the stress response in Hsf1 null mice will affect the rate or severity of age-related hearing loss. Studies in Aim 4, which interface with studies in Project 0001, will test the hypothesis that both antioxidant defenses and the inducible stress response contribute to age-related hearing loss. Hsf1 null mice and their wild-type littermates will be maintained on an oxidant-supplemented diet from 8 months to test the effect of antioxidants on ARHL and the stress response. Aim 5 will generate and characterize two additional transgenic mouse models that express a constitutively active form of HSF1 in the cochlea. These studies of the inducible stress response in the aging cochlea will provide a better understanding of the role of this important protective pathway in ARHL and will provide a rational basis for future interventions to prevent and/or treat presbycusis.
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