skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Neurobehavioral Mutants Identified in an ENU Mutagenesis Project

Abstract

We report on a behavioral screening test battery that successfully identified several neurobehavioral mutants among a large-scale ENU-mutagenized mouse population. Large numbers of ENU mutagenized mice were screened for abnormalities in central nervous system function based on abnormal performance in a series of behavior tasks. We developed and employed a high-throughput screen of behavioral tasks to detect behavioral outliers. Twelve mutant pedigrees, representing a broad range of behavioral phenotypes, have been identified. Specifically, we have identified two open field mutants (one displaying hyper-locomotion, the other hypo-locomotion), four tail suspension mutants (all displaying increased immobility), one nociception mutant (displaying abnormal responsiveness to thermal pain), two prepulse inhibition mutants (displaying poor inhibition of the startle response), one anxiety-related mutant (displaying decreased anxiety in the light/dark test), and one learning and memory mutant (displaying reduced response to the conditioned stimulus) These findings highlight the utility of a set of behavioral tasks used in a high throughput screen to identify neurobehavioral mutants. Further analysis (i.e., behavioral and genetic mapping studies) of mutants is in progress with the ultimate goal of identification of novel genes and mouse models relevant to human disorders as well as the identification of novel therapeutic targets.

Authors:
 [1];  [1];  [2];  [3];  [3];  [4]
  1. University of Memphis
  2. Vanderbilt University and Veterans Administration, Nashville, TN
  3. ORNL
  4. University of Tennessee Health Science Center, Memphis
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mouse Genetics Research Facility
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
958787
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Mammalian Genome; Journal Volume: 18; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CENTRAL NERVOUS SYSTEM; GENES; GENETIC MAPPING; LEARNING; MICE; MUTAGENESIS; MUTANTS; PERFORMANCE; SCREENS; TARGETS; ENU; Behavior; Mutagenesis; Mutant

Citation Formats

Cook, Melloni N., Dunning, Jonathan P, Wiley, Ronald G, Chesler, Elissa J, Johnson, Dabney K, and Goldowitz, Daniel. Neurobehavioral Mutants Identified in an ENU Mutagenesis Project. United States: N. p., 2007. Web. doi:10.1007/s00335-007-9035-3.
Cook, Melloni N., Dunning, Jonathan P, Wiley, Ronald G, Chesler, Elissa J, Johnson, Dabney K, & Goldowitz, Daniel. Neurobehavioral Mutants Identified in an ENU Mutagenesis Project. United States. doi:10.1007/s00335-007-9035-3.
Cook, Melloni N., Dunning, Jonathan P, Wiley, Ronald G, Chesler, Elissa J, Johnson, Dabney K, and Goldowitz, Daniel. Mon . "Neurobehavioral Mutants Identified in an ENU Mutagenesis Project". United States. doi:10.1007/s00335-007-9035-3.
@article{osti_958787,
title = {Neurobehavioral Mutants Identified in an ENU Mutagenesis Project},
author = {Cook, Melloni N. and Dunning, Jonathan P and Wiley, Ronald G and Chesler, Elissa J and Johnson, Dabney K and Goldowitz, Daniel},
abstractNote = {We report on a behavioral screening test battery that successfully identified several neurobehavioral mutants among a large-scale ENU-mutagenized mouse population. Large numbers of ENU mutagenized mice were screened for abnormalities in central nervous system function based on abnormal performance in a series of behavior tasks. We developed and employed a high-throughput screen of behavioral tasks to detect behavioral outliers. Twelve mutant pedigrees, representing a broad range of behavioral phenotypes, have been identified. Specifically, we have identified two open field mutants (one displaying hyper-locomotion, the other hypo-locomotion), four tail suspension mutants (all displaying increased immobility), one nociception mutant (displaying abnormal responsiveness to thermal pain), two prepulse inhibition mutants (displaying poor inhibition of the startle response), one anxiety-related mutant (displaying decreased anxiety in the light/dark test), and one learning and memory mutant (displaying reduced response to the conditioned stimulus) These findings highlight the utility of a set of behavioral tasks used in a high throughput screen to identify neurobehavioral mutants. Further analysis (i.e., behavioral and genetic mapping studies) of mutants is in progress with the ultimate goal of identification of novel genes and mouse models relevant to human disorders as well as the identification of novel therapeutic targets.},
doi = {10.1007/s00335-007-9035-3},
journal = {Mammalian Genome},
number = 8,
volume = 18,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • The Tennessee Mouse Genome Consortium (TMGC) employed an N-ethyl-N-nitrosourea (ENU)-mutagenesis scheme to identify mouse recessive mutants with hearing phenotypes. We employed auditory brainstem responses (ABR) to click and 8, 16, and 32 kHz stimuli and screened 285 pedigrees (1819 mice of 8-11 weeks old in various mixed genetic backgrounds) each bred to carry a homozygous ENU-induced mutation. To define mutant pedigrees, we measured P12 mice per pedigree in P2 generations and used a criterion where the mean ABR threshold per pedigree was two standard deviations above the mean of all offspring from the same parental strain. We thus identified 17more » mutant pedigrees (6%), all exhibiting hearing loss at high frequencies (P16 kHz) with an average threshold elevation of 30-35 dB SPL. Interestingly, four mutants showed sex-biased hearing loss and six mutants displayed wide range frequency hearing loss. Temporal bone histology revealed that six of the first nine mutants displayed cochlear morphological defects: degeneration of spiral ganglia, spiral ligament fibrocytes or inner hair cells (but not outer hair cells) mostly in basal turns. In contrast to other ENU-mutagenesis auditory screens, our screen identified high-frequency, mild and sex-biased hearing defects. Further characterization of these 17 mouse models will advance our understanding of presbycusis and noise-induced hearing loss in humans.« less
  • Four independent ENU induced mutations associated with a 50% loss of triosephosphate isomerase (TPI) activity have been identified in mouse germinal mutation experiments. Genomic PCR amplification products using primers homologous to the intron regions of the TPI gene from control and mutant mice were directly sequenced to determine the molecular lesion in each of these mutants. Mutants Tpi*M-1NEU and Tpi*M-2NEU carried the same T:A to A:T transversion, resulting in a Leu to Glu substitution at residue 192. Residue 192 is located in {alpha}-helix H6, on the surface of the protein. Analysis of the Tpi*M-3NEU allele revealed an A:T to C:Gmore » transversion changing the stop codon to Cys, resulting in the addition of 19 amino acids. The fourth mutant, Tpi*M-4NEU, was another T:A to A:T transversion resulting in a Leu to Glu substitution, this time at residue 162. This mutation is situated next to a region conserved in all TPI genes sequenced. It is placed at the beginning at {beta}-strand B6 in the immediate vicinity of the active site residue Glu 165. These mutants provide insight into the mechanism of ENU mutagenesis and can serve as models for structure-function studies of the interesting enzyme where most of the variants are null variants rather than electromorphs.« less
  • Highlights: •Inhibitors against MDR HIV-1 protease were designed, synthesized and evaluated. •Lead peptide (6a) showed potent inhibition (IC{sub 50}: 4.4 nM) of MDR HIV-1 protease. •(6a) Showed favorable binding isotherms against NL4-3 and MDR proteases. •(6a) Induced perturbations in the {sup 15}N-HSQC spectrum of MDR HIV-1 protease. •Molecular modeling suggested that (6a) may induce total flap closure inMDR protease. -- Abstract: Multidrug-resistant (MDR) clinical isolate-769, human immunodeficiency virus type-1 (HIV-1) protease (PDB ID: (1TW7)), was shown to exhibit wide-open flaps and an expanded active site cavity, causing loss of contacts with protease inhibitors. In the current study, the expanded activemore » site cavity of MDR769 HIV-1 protease was screened with a series of peptide-inhibitors that were designed to mimic the natural substrate cleavage site, capsid/p2. Scanning Ala/Phe chemical mutagenesis approach was incorporated into the design of the peptide series to mimic the substrate co-evolution. Among the peptides synthesized and evaluated, a lead peptide (6a) with potent activity (IC{sub 50}: 4.4 nM) was identified against the MDR769 HIV-1 protease. Isothermal titration calorimetry data showed favorable binding profile for 6aagainst both wild type and MDR769 HIV-1 protease variants. Nuclear magnetic resonance spectrum of {sup 15}N-labeled MDR769 HIV-1 protease in complex with 6a showed some major perturbations in chemical shift, supporting the peptide induced conformational changes in protease. Modeling analysis revealed multiple contacts between 6a and MDR769 HIV-1 protease. The lead peptide-inhibitor, 6a, with high potency and good binding profile can be used as the basis for developing potent small molecule inhibitors against MDR variants of HIV.« less