scholarly journals Kiss of the Mutant Mouse: How Genetically Altered Mice Advanced Our Understanding of Kisspeptin's Role in Reproductive Physiology

Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5119-5129 ◽  
Author(s):  
Heather M. Dungan Lemko ◽  
Carol F. Elias

Abstract The kisspeptin system has emerged as one of the most important circuits within the central network governing reproduction. Although kisspeptin physiology has been examined in many species, much of our understanding of this system has come from mice. Recently, the study of several innovative strains of genetically engineered mouse models has revealed intriguing and unexpected insights into the functions of kisspeptin signaling in the hypothalamus. Here, we review the advancements in our knowledge of the central kisspeptin system through the use of mutant mice.

2018 ◽  
Author(s):  
Mathilde Soulez ◽  
Marc K. Saba-El-Leil ◽  
Benjamin Turgeon ◽  
Simon Mathien ◽  
Philippe Coulombe ◽  
...  

AbstractThe physiological functions of the atypical MAP kinase ERK3 remain poorly characterized. Previous analysis of mice with a targeted insertion of the lacZ reporter in the Mapk6 locus (Mapk6lacZ) showed that inactivation of ERK3 in Mapk6lacZ mice leads to perinatal lethality associated with intrauterine growth restriction, defective lung maturation, and neuromuscular anomalies. To further explore the role of ERK3 in physiology and disease, we generated novel mouse models expressing a catalytically-inactive (Mapk6KD) or conditional (Mapk6Δ) allele of ERK3. Surprisingly, we found that mice devoid of ERK3 kinase activity or expression survive the perinatal period without any observable lung or neuromuscular phenotype. ERK3 mutant mice reached adulthood, were fertile and showed no apparent health problem. However, analysis of growth curves revealed that ERK3 kinase activity is ncessary for optimal post-natal growth. To gain insight into the genetic basis underlying the discrepancy in phenotypes of different Mapk6 mutant mouse models, we analyzed the regulation of genes flanking the Mapk6 locus by quantitative PCR. We found that expression of several Mapk6 neighboring genes is deregulated in Mapk6lacZ mice, but not in Mapk6KD or Mapk6Δ mutant mice. Our genetic analysis suggests that off-target effects of the targeting construct on local gene expression are likely to be responsible for the perinatal lethality phenotype of Mapk6lacZ mutant mice.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii295-iii295
Author(s):  
Annette Wu ◽  
Tak Mak ◽  
Jerome Fortin

Abstract Diffuse midline gliomas (DMGs) are aggressive childhood brain tumors with a dismal prognosis. Most of these tumors carry K27M mutations in histone H3-encoding genes, particularly H3F3A and HIST1H3B. In addition, activating mutations in ACVR1 and PIK3CA co-occur in a subset of DMGs. To understand how these lesions drive the development of DMGs, we generated genetically engineered mouse models in which Acvr1G328V, Hist1h3bK27M, and Pik3caH1047R are targeted to the OLIG2-expressing cell lineage. Animals carrying Acvr1G328V and Pik3caH1047R, with (“AHPO”) or without (“APO”) Hist1h3bK27M, developed high-grade diffuse gliomas involving midline and forebrain regions. Neither Acvr1G328V nor Pik3caH1047R drove tumorigenesis by themselves, but Acvr1G328V was sufficient to cause oligodendroglial differentiation arrest, pointing to a role in the earliest stages of gliomas formation. Transcriptomic analyses of AHPO and APO tumors indicated a predominantly proneural and oligodendrocyte precursor-like gene expression signature, consistent with the corresponding human pathology. Genes encoding transcription factors (TFs) with dual roles in controlling glial and neuronal differentiation were upregulated in tumors. Some of these genes were mildly induced by Acvr1G328V alone. Functional experiments using CRISPR/Cas9-mediated gene editing in patient-derived cell lines confirmed a role for some of these TFs in controlling DMG cell fitness. Overall, our results suggest that Pik3caH1047R consolidates Acvr1G328V-induced glial differentiation arrest to drive DMG development and progression.


2016 ◽  
Vol 113 (42) ◽  
pp. E6409-E6417 ◽  
Author(s):  
David G. McFadden ◽  
Katerina Politi ◽  
Arjun Bhutkar ◽  
Frances K. Chen ◽  
Xiaoling Song ◽  
...  

Genetically engineered mouse models (GEMMs) of cancer are increasingly being used to assess putative driver mutations identified by large-scale sequencing of human cancer genomes. To accurately interpret experiments that introduce additional mutations, an understanding of the somatic genetic profile and evolution of GEMM tumors is necessary. Here, we performed whole-exome sequencing of tumors from three GEMMs of lung adenocarcinoma driven by mutant epidermal growth factor receptor (EGFR), mutant Kirsten rat sarcoma viral oncogene homolog (Kras), or overexpression of MYC proto-oncogene. Tumors from EGFR- and Kras-driven models exhibited, respectively, 0.02 and 0.07 nonsynonymous mutations per megabase, a dramatically lower average mutational frequency than observed in human lung adenocarcinomas. Tumors from models driven by strong cancer drivers (mutant EGFR and Kras) harbored few mutations in known cancer genes, whereas tumors driven by MYC, a weaker initiating oncogene in the murine lung, acquired recurrent clonal oncogenic Kras mutations. In addition, although EGFR- and Kras-driven models both exhibited recurrent whole-chromosome DNA copy number alterations, the specific chromosomes altered by gain or loss were different in each model. These data demonstrate that GEMM tumors exhibit relatively simple somatic genotypes compared with human cancers of a similar type, making these autochthonous model systems useful for additive engineering approaches to assess the potential of novel mutations on tumorigenesis, cancer progression, and drug sensitivity.


2021 ◽  
pp. 112757
Author(s):  
Reihaneh Alsadat Mahmoudian ◽  
Moein Farshchian ◽  
Mohammad Reza Abbaszadegan

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Mei Methawasin ◽  
Kirk R Hutchinson ◽  
John E Smith ◽  
Henk L Granzier

Titin, a myofilament that acts as a molecular spring in the sarcomere, is considered the main contributor to passive stiffness of cardiomyocytes and is responsible for cardiac diastolic function. Increased titin stiffness is related to diastolic dysfunction and HFpEF (Heart Failure with preserved Ejection Fraction). Alteration in size of titin’s spring region leads to changes in cardiomyocyte and left ventricular (LV) chamber stiffness. We tested the effect of alteration in titin’s size in two genetically engineered mouse models. We investigated the effect of shortening titin’s spring region in a mouse model in which I-band/A-band region of titin’s spring has been deleted (TtnΔIAjxn ), in comparison to the effect of lengthening titin’s spring region in a mouse model deficient in titin splicing factor (Rbm20ΔRRM). Integrative approaches were used from single cardiomyocyte mechanics to pressure-volume analysis and exercise study. Study of skinned LV cardiomyocytes revealed that cellular passive stiffness was inversely related to the size of titin. Cellular passive stiffness was increased in TtnΔIAjxn homozygous (-/-) (~ 110 % higher than wildtype (WT)) and was reduced in a graded manner in Rbm20ΔRRM heterozygous (+/-) and -/- cardiomyocytes (~61% and ~87% less than WT). This effect was carried through at the LV chamber level which could be demonstrated in pressure volume (PV) analysis as an increased end-diastolic pressure-volume relationship (EDPVR) in TtnΔIAjxn -/- (~110% higher than WT’s hearts) and reduced EDPVR in Rbm20ΔRRM +/- and -/- (~57% and ~48% less than WT’s hearts). Free-wheel running studies revealed a running deficiency in TtnΔIAjxn -/- mice but an increase in exercise capacity in Rbm20ΔRRM +/– mice. Conclusions: Functional studies from the cellular to in-vivo LV chamber levels showed that mice with shortening of titin’s spring region had increased LV stiffness, diastolic dysfunction and reduced exercise capacity, while mice with lengthening titin’s spring region had compliant LV and increased exercise capacity. Thus, our work supports titin’s important roles in LV diastolic function and suggests that modification of the size of titin’s spring region could be a potential therapeutic strategy for HFpEF.


2018 ◽  
Vol 9 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Troy L. Merry ◽  
Maxim S. Petrov

AbstractPancreatitis is increasingly recognized as not merely a local inflammation of the pancreas but also a disease with high frequency of systemic sequelae. Current understanding of the cellular mechanisms that trigger it and affect the development of sequelae are limited. Genetically engineered mouse models can be a useful tool to study the pathophysiology of pancreatitis. This article gives an overview of the genetically engineered mouse models that spontaneously develop pancreatitis and discusses those that most closely replicate different pancreatitis hallmarks observed in humans.


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