Utility and limits of Hprt-Cre technology in generating mutant mouse embryos

Abstract

Background Hprt-Cre doubles the prevalence of homozygous null embryos per litter versus heterozygous breedings without decreasing litter size. Resulting mutant embryos are genotypically and phenotypically equivalent between strategies. We set out to confirm the effectiveness of this approach with other alleles and hypothesized that it would increase efficiency in generating compound mutants. Materials and methods Null mutants for Cyp26b1, Pitx2, and Shh were generated with Hprt-Cre from conditional alleles as were double and triple allelic combinations of Fgfr2IIIb, Raldh2, and Cyp26b1. Embryos were genotyped and phenotyped by whole mount photography, histology, and immunohistochemistry. Results Fifty percent of Hprt-Cre litters were homozygous null for Cyp26b1 (15/29) and Pitx2 (75/143), with phenotypic and genotypic equivalence to mutants from standard heterozygous breedings. In multi-allele breedings, mutant embryos constituted half of litters without significant embryo loss. In contrast, Shh breedings yielded a smaller ratio of embryos carrying two recombined alleles (6 of 16), with a significant litter size reduction because of early embryonic lethality (16 live embryos from 38 deciduae). Conclusions Hprt-Cre can be used to efficiently generate large numbers of mutant embryos with a number of alleles. Compound mutant generation was equally efficient. However, efficiency is reduced for genes whose protein product potentially interacts with the Hprt pathway (e.g., Shh).

Selecting Species for Pharmaceutical and Medical Research

“…Furthermore, genetic similarities exist between Zebrafish and humans, which made them a model to study diseases such as leukemia and some other cancers. Importantly, genetically modifies animals, such as Cre-mutant mouse strains [46][47][48] represent an essential tool in biological and medical research. Indeed, family Alzheimer disease (FAD) genes are introduced to monkeys and mice brains through transgenic virus as one of the methods, among others, [49][50][51][52][53] used to obtain animals models of Alzheimer disease (AD) 29 used to study AD properties, pathogenesis, mechanisms and test therapeutic candidates.…”

Paired‐like homeodomain transcription factor 2 affects endometrial cell function and embryo implantation through the Wnt/β‐catenin pathway

“…PITX2 is involved in various cellular functions (e.g., growth and differentiation) and essential for organogenesis and morphogenesis during early embryonic development. Zaremba et al (2014) used the Hprt‐Cre breeding strategy to significantly improve the efficiency of PITX2 to homozygous null mutants, and Pitx2 rec/rec mutants showed incomplete closure of the abdominal wall with ectopic viscera including the lungs, heart, and intestine. Abnormal PITX2 expression is associated with a variety of diseases, including Axenfeld‐Rieger syndrome (Semina et al, 1996), arrhythmia (Wang et al, 2010), and atrial fibrillation (Kirchhof et al, 2011).…”