Microbiological survey of Korean mouse facilities from 2014 to 2019.

We surveyed mouse microbiological contamination rates by testing rates for common contaminants using serological, culture, and parasitological methods. A total of 21,292 experimentally housed mice from 206 animal facilities, including hospitals, universities, companies, and research institutes, were tested over a 6-year period from 2014 to 2019. The most commonly found contaminants were various species of nonpathogenic protozoa (47.2%). The most common pathogenic bacteria were Staphylococcus aureus (21.2%), Pasteurella pneumotropica (12.5%), and Pseudomonas aeruginosa (5.8%). Mouse hepatitis virus (6.1%) was detected, but no other viral or bacterial pathogens were found. These results establish that the main pathogens that currently contaminate mouse facilities in Korea are opportunistic pathogens and that contamination with important pathogens, such as those in Categories B or C, has decreased.

Importin-11 is Essential for Normal Embryonic Development in Mice.

Importin-11 (Ipo11) is a novel member of the human importin family of transport receptors (karyopherins), which are known to mediate the nucleocytoplasmic transport of protein and RNA cargos. Despite its role in the transport of protein, we found that knockout of Ipo11 nuclear import factor affects normal embryonic development and govern embryo-lethal phenotypes in mice. In this study, we for the first time produced a mouse line containing null mutation in Ipo11 gene utilized by gene trapping. The Ipo11-/- embryos showed an embryonic lethal phenotype. The Ipo11-/- embryos showed a reduced size at embryonic day 10.5 (E10.5) when compared with Ipo11+/+ or Ipo11+/- embryos and died by E11.5. Whereas Ipo11+/- mice were healthy and fertile, and there was no detectable changes in embryonic lethality and phenotype when reviewed. In the X-gal staining with the Ipo11-/- or Ipo11+/- embryos, strong X-gal staining positivity was detected systematically in the whole mount embryos at E10.5, although almost no X-gal positivity was detected at E9.5, indicating that the embryos die soon after the process of Ipo11 expression started. These results indicate that Ipo11 is essential for the normal embryonic development in mice.

Critical Roles of E2F3 in Growth and Musculo-skeletal Phenotype in Mice.

E2F3, a member of the E2F family, plays a critical role in cell cycle and proliferation by targeting downstream, retinoblastoma (RB) a tumor suppressor family protein. The purpose of this study, was to investigate the role and function of E2F3 in vivo. We examined phenotypic abnormalities, by deletion of the E2f3 gene in mice. Complete ablation of the E2F3 was fully penetrant, in the pure C57BL/6N background. The E2f3+/ - mouse embryo developed normally without fatal disorder. However, they exhibited reduced body weight, growth retardation, skeletal imperfection, and poor grip strength ability. Findings suggest that E2F3 has a pivotal role in muscle and bone development, and affect normal mouse growth.