Page 62 - Mouse Molecular Genetics

Full Abstracts
Program number is above title. Author in bold is the presenter.
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C57BL/6NTac double and single albino mice generation for efficient germline transmission of Chimera. Ana V. Perez
1
,
Gunther Kauselmann
2
,
Maria R. Da Silva
2
,
Heidrun Kern
2
,
Nathalie Uyttersprot
2
,
Gerald Bothe
3
,
Branko Zevnik
2
. 1)
Genetic
Sciences & Compliance, Taconic, Hudson, NY; 2) Applied Genetics, Taconic Artemis GmbH, Cologne, Germany; 3) R&D,
Taconic, Rensselaer, NY.
Coat color is usually an easy way to visualize contributions of mouse embryonic stem (ES) cells injected into host blastocysts
during generation of genetically modified models, both being of different coat colors. Furthermore, coat color becomes important
in order to visually determine germline transmission of the ES cell genome. C57BL/6 is the preferred genetic background of use.
Therefore, the use of C57BL/6 mouse ES cells that produce black mice have become the ES cells of choice. In this scenario the
preferred host blastocysts used are from albino (white) colored mouse strains such as C57BL/6 albino mice, that have arose as
spontaneous mutants, or BALB/c mice. BALB/c mice respond poorly to superovulation resulting in low blastocyst yields which
in turn results in usage of more mice. The increase in numbers of females for superovulation is counterproductive due to higher
expense and animal use in research. Available albino C57BL/6 strains provide a suitable alternative but due to the recessive
nature of the
Tyr
c
mutation, coat-color detection of ES cell contribution in germline transmitted G1 offspring requires breeding of
chimeras to albino C57BL/6. More importantly, a pure genetic C57BL/6 substrain background may only be maintained by
subsequent backcrossing and in addition the need to breed out the
Tyr
c
allele that will be inherited by the progeny if it is not
actively screened against and removed from the colony. We decided to address the problems outlined above by generating a
genetically modified C57BL/6NTac mouse albino model that carries the reversion of the non-agouti locus to a dominant agouti
(
A) allele,
A
tm1.1Arte
,
and the loss-of-function of the tyrosinase locus by a genetically engineered point mutation, the albino
allele,
Tyr
tm1Arte
.
When this double mutant, C57BL/6NTac-
A
tm1.1Arte
Tyr
tm1Arte
is used as host blastocyst with C57BL/6 ES cells,
the resulting black/albino chimeras can be mated directly to C57BL/6 mice and allow recognition of germline transmission in the
G1 offspring just by coat color. In addition, our data shows that the superovulation response of the double mutant albino is
similar to C57BL/6NTac and that there is effective germline transmission when using these double albino mutants as host
blastocysts.
81
Disentangling the genetic architecture of nest building: a fitness-related trait. Andrea Cristina Peripato
1,2
,
Bruno Sauce
1
,
Reinaldo Alves de Brito
1
. 1)
Genetics and Evolution, University of Sao Carlos, Sao Carlos, SP, Brazil; 2) Biosciences, University
of Sao Paulo, Santos, SP, Brazil.
Nest building in mammals is set by an important array of maternal behaviors that ensures pups survival and it is directly
associated with fitness. Here we investigated the genetic architecture of nest building in F2 mice LG/J x SM/J. We performed a
QTL analysis by using 101 microsatellites markers and six related nest phenotypes (Presence and Structure pre- and postpartum,
prepartum Material Used and postpartum Temperature). We found 15 single QTLs, mostly with non-additive effect that explain
individually from 4 to 13% of the phenotypic variation of nest building phenotypes. We also found 71 regions interacting
epistatically which, along with single QTLs, explain from 28.4 to 75.5% of variation for nest building phenotypes. Our results
indicate a genetic architecture with small direct effects and a larger number of epistatic interactions as it is suggested to be the
case for fitness-related phenotypes when compared to non-fitness-related phenotypes. We conclude that nest building is a
complex maternal behavior critical to offsprings survival and development and in which epistasis plays an important role in their
adaptive process. Financial Support: FAPESP.
82
Genetic Studies of Inflammatory Responses in Wild-Derived Mice. Alexander N. Poltorak
.
Tufts University, Boston, MA.
Immune response leads to inflammation which, if excessive, can often lead to the programmed death. How do genes control the
balance between inflammation and cell death? To answer this question, we have elected to study the immune responses in so
called wild-derived mice (WDM), which evolved from common ancestor with classical laboratory mice more than a million years
ago and therefore share only 11% of their genome with laboratory mice. Such divergence of WDM results in phenotypic
differences between WDM and classical laboratory mice, which we investigate by means of classical genetic analysis. In the last
few years, we established several genetic screens in the WDM including hyper- and hypo-responsiveness to TLR-agonists,
resistance to TLR-mediated necroptosis, in vitro responses to infectious pathogens, resistance to septic shock in vivo. In our
published and ongoing research, we show that forward studies in WDM provide insights into human biology that would not be
available without access to this largely untapped reservoir of genetic diversity.
83
Comprehensive molecular characterization of mutant mouse strains generated from the EUCOMM / KOMP ES cell
resource. Ed Ryder
,
Diane Gleeson, Debarati Sethi, Sapna Vyas, Evelina Miklejewska, Priya Dalvi, Bishoy Habib, Ross Cook,
Matthew Hardy, Joanna Bottomley, David Adams, Ramiro Ramirez-Solis, Sanger Mouse Genetics Project. Wellcome Trust
Sanger Institute, Cambridge, United Kingdom.
The EUCOMM/KOMP mouse embryonic stem cell collection, which is based on JM8 agouti or non-agouti C57BL/6N ES cells
is currently the biggest single resource of targeted mutations available for the mouse. The Wellcome Trust Sanger Institute
Mouse Genetics Project (Sanger MGP) generates the strains from these clones, and characterizes the phenotypic consequences of
the modified alleles in a high-throughput primary phenotypic analysis pipeline. Strains are available from the EMMA or KOMP