Page 58 - Mouse Molecular Genetics

Full Abstracts
Program number is above title. Author in bold is the presenter.
58
for Wdr5 recruitment and H3K4 methylation at key regulatory loci, highlighting complexity and interconnectivity of various
chromatin regulators in ESCs.
Genetics and Genomics
69
Construction of reciprocal chromosome substitution strains from 129P3/J and C57BL/6ByJ mice. Alexander A.
Bachmanov
,
Cailu Lin, Natalia P. Bosak, Theodore M. Nelson, Maria L. Theodorides, Zakiyyah H. Smith, Matthew T. Kirkey,
Mauricio Avigdor, Brian R. Gantick, M. Amin Khoshnevisan, Anna Lysenko, Danielle R. Reed. Monell Chemical Senses Center,
Philadelphia, PA.
The 129P3/J and C57BL/6ByJ inbred strains differ in taste responses, ingestive behavior, alcohol consumption, body size and
adiposity. Genome scans of crosses between these strains have detected QTLs for these phenotypes that cluster on chromosomes
(
Chr) 1, 2, 7 and 9 (
Adip2, Adip3, Adip5, Ap7q, Bwq5, Bwq6, Nattq1, Nattq2, Sucq
).
Chromosome substitution strains (CSSs) are
a useful resource for positional identification of these QTLs, but extant B6 and 129 CSSs involve different substrains
(129
S1/SvImJ and C57BL/6J), which are genetically and phenotypically distinct from the substrains used in our studies. We
therefore initiated construction of reciprocal CSSs for Chr 1, 2, 7 and 9 from the 129P3/J and C57BL/6ByJ strains using a "speed
consomics" approach. During the first two backcross generations (N2 and N3) a genome scan was conducted to identify optimal
breeders. In subsequent backcrosses, donor chromosomes were genotyped to prevent the loss of fragments due to double-
crossovers. To ensure that the QTLs were retained, we phenotyped several incipient strains and conducted linkage analyses; these
analyses confirmed the original QTLs on Chr 1 (
Nattq1
),
Chr 2 (
Bwq5, Adip2
),
Chr 7 (
Ap7q; Adip3
)
and Chr 9 (
Natt2q, Bwq6,
Adip5, Sucq
).
Some CSS strains are now complete (129P3/J-Chr 7
C57B6/ByJ
,
C57B6/ByJ-Chr 2
129
P3/J
,
C57B6/ByJ-Chr 7
129
P3/J
,
C57B6/ByJ-Chr 9
129
P3/J
)
and others are nearing completion. Supported by National Institutes of Health (NIH) grants
R01DC000882, R01AA011028 (A.A.B), R01DK058797, DK094759 and the Center for Inherited Disease Research (CIDR)
(
D.R.R.).
70
Generation of CreERT2 transgenic mouse lines for time and cell specific conditional gene inactivation Validation of 3
pancreas specific lines : Insulin1, Glucagon et Elastase-CreER
T2
.
Marie-Christine Birling
1
,
Lydie Venteo
1
,
Olivia
Wendling
1,2
,
Nathalie Chartoire
1
,
Marie-France Champy
1
,
Elodie Bedu
1
,
Tania Sorg
1
,
Yann Hérault
1,2
,
Guillaume Pavlovic
1
. 1)
Genetic Engineering, Institut Clinique de la Souris, 1, rue Laurent Fries, 67400 Illkirch, France; 2) IGBMC, 1, rue Laurent Fries,
67400
Illkirch, France.
The generation of mouse mutants using conventional knock out approach is a powerful tool to study the role of specific genes.
However, this technology shows two major limitations: (i) disruption of many genes result in lethal phenotypes (ii) it does not
allow site specific and time controlled inactivation of a gene. The conditional knock-out strategy overcomes these limitations.
When such floxed mice are bred with transgenic mice expressing the Cre recombinase in a tissue/cell-specific manner, the gene
of interest is knocked out/altered only in this particular tissue or cell type. An added sophistication is the inclusion of temporal
control, which can be achieved using a ligand-activated chimeric recombinase, composed of the fusion of the Cre recombinase
with the ligand binding domain of a mutated form of the estrogen receptor (ER), which can only be activated by synthetic ER
ligands (e.g. tamoxifen, Cre -ER
T2
,
Indra et al. 1999). Large-scale international mouse mutagenesis programs (see IKMP) are
providing conditional knock-out of most mouse genes. As these lines are available to the whole scientific community, the need of
a large variety of cell specific deleter lines is essential. At the ICS, we have generated about 50 Cre transgenic mouse lines
expected to express the tamoxifen inducible CreER
T2
recombinase in different target tissues and cells. They are available to the
research community and are a powerful tool for the study of disease genes function, the creation of disease models and to answer
questions on the cell/organ autonomous or not character of various pathological phenotypes. For details, please see
We will give you an example of 3 fully characterized mouse line: Insulin1-, Glucagon- and
Elastase-CreERT2. For the Insulin1-CreERT2 line, the Cre expression is observed in the -cells, the translocation in the nucleus is
confirmed in the presence of Tamoxifen as expected for an inducible line. By breeding this line with Rosa26 reporter line, a
specific LacZ staining is observed in the -islet cells. This line was phenotyped (under chow diet) and no glucose intolerance was
observed at the difference of the Rat Insulin Promoter (RIP)-Cre line. A comparative study (Ins1-CreERT2 versus RIP-Cre) was
performed and will be detailed. Similarly, the Glucagon-CreERT2 line is specific for alpha-cells and elastase-CreERT2 line is
specific from acinar cells. Further phenotyping are under way and will be discussed;.
71
Developmental dynamics of the Tbx18 locus and its downstream transcriptional targets. C. Chase Bolt
1
,
Xiaochen Lu
1
,
Laura Chittenden
1
,
Nuno Camboa
2
,
Sylvia Evans
3
,
Lisa J. Stubbs
1
. 1)
Dept. of Cellular and Developmental Biology, Institute for
Genomic Biology, University of Illinois - Urbana/Champaign, Urbana, IL; 2) Skaggs School of Pharmacy and Pharmaceutical
Sciences, University of California, San Diego, CA, GABBA Graduate Program and ICBAS, University of Porto, Portugal; 3)