Analysis of a quantitative trait locus for seizure susceptibility in mice using bacterial artificial chromosome-mediated gene transfer.
OBJECTIVE
Previous quantitative trait loci (QTL) mapping studies from our laboratory identified a 6.6 Mb segment of distal chromosome 1 that contains a gene (or genes) having a strong influence on the difference in seizure susceptibility between C57BL/6 (B6) and DBA/2 (D2) mice. A gene transfer strategy involving a bacterial artificial chromosome (BAC) DNA construct that contains several candidate genes from the critical interval was used to test the hypothesis that a strain-specific variation in one (or more) of the genes is responsible for the QTL effect.


METHODS
Fertilized oocytes from a seizure-sensitive congenic strain (B6.D2-Mtv7a/Ty-27d) were injected with BAC DNA and three independent founder lines of BAC-transgenic mice were generated. Seizure susceptibility was quantified by measuring maximal electroshock seizure threshold (MEST) in transgenic mice and nontransgenic littermates.


RESULTS
Seizure testing documented significant MEST elevation in all three transgenic lines compared to littermate controls. Allele-specific RT-PCR analysis confirmed gene transcription from genome-integrated BAC DNA and copy-number-dependent phenotypic effects were observed.


CONCLUSIONS
Results of this study suggest that the gene(s) responsible for the major chromosome 1 seizure QTL is found on BAC RPCI23-157J4 and demonstrate the utility of in vivo gene transfer for studying quantitative trait genes in mice. Further characterization of this transgenic model will provide new insight into mechanisms of seizure susceptibility.
Ferraro
Thomas N
TN
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Golden
Gregory T
GT
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Dahl
John P
JP
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Smith
George G
GG
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Schwebel
Candice L
CL
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
MacDonald
Ross
R
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Lohoff
Falk W
FW
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Berrettini
Wade H
WH
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
Buono
Russell J
RJ
Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PennsylvaniaResearch Service, Veteran's Affairs Medical Center, Coatesville, PennsylvaniaDepartment of Neurology, University of Cincinnati, Cincinnati, Ohio, U.S.A.
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics*; D004195:Disease Models, Animal; D004597:Electroshock; D005260:Female; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D020022:Genetic Predisposition to Disease / Q000235:genetics; D008297:Male; D051379:Mice; D020297:Mice, Congenic; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008957:Models, Genetic; D040641:Quantitative Trait Loci / Q000235:genetics*; D012640:Seizures / Q000235:genetics* / Q000378:metabolism