A timely, user-friendly, and flexible marker-assisted speed congenics method.

Mice are the most widely used mammalian animal model worldwide. Their use presents many advantages, including our ability to manipulate their genome. Unfortunately, transgenic mice often need to be introgressed to transfer the transgene of interest in a specific mouse line. This time-consuming process can be shortened using the speed congenics technique. However, the need for a panel of informative markers to evaluate the proportion of donor and receiver genomes in different individuals produced at each generation hinders the utilisation of speed congenics. In this study, we present 255 microsatellites and 10 RFLPs which can be used in 18 marker panels, allowing the easy and fast introgression of genes of interest from three mouse lines commonly used for transgenesis (C57BL/6, 129/Sv and FVB) to six mouse lines relevant for biomedical research (BALB/c, C3H, DBA/1, DBA/2, SJL and SWR/J). In addition, our markers analysis confirmed a recently described lack of isogeny in well-established inbred mouse lines available from commercial breeders.

Longitudinal quantitative assessment of TMEV-IDD-induced MS phenotypes in two inbred mouse strains using automated video tracking technology.

Multiple sclerosis (MS) is a chronic disabling disease of the central nervous system affecting over 2.5 million people worldwide. Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) is a murine model that reproduces the progressive form of MS and serves as a reference model for studying virus-induced demyelination. Certain mouse strains such as SJL are highly susceptible to this virus and serve as a prototype strain for studying TMEV infection. Other strains such as SWR are also susceptible, but their disease course following TMEV infection differs from SJL's. The quantification of motor and behavioral deficits following the induction of TMEV-IDD could help identify the differences between the two strains. Motor deficits have commonly been measured with the rotarod apparatus, but a multicomponent assessment tool has so far been lacking. For that purpose, we present a novel way of quantifying locomotor deficits, gait alterations and behavioral changes in this well-established mouse model of multiple sclerosis by employing automated video analysis technology (The PhenoTyper, Noldus Information Technology). We followed 12 SJL and 12 SWR female mice and their mock-infected counterparts over a period of 9 months following TMEV-IDD induction. We demonstrated that SJL and SWR mice both suffer significant gait alterations and reduced exploration following TMEV infection. However, SJL mice also display an earlier and more severe decline in spontaneous locomotion, especially in velocity, as well as in overall activity. Maintenance behaviors such as eating and grooming are not affected in either of the two strains. The system also showed differences in mock-infected mice from both strains, highlighting an age-related decline in spontaneous locomotion in the SJL strain, as opposed to hyperactivity in the SWR strain. Our study confirms that this automated video tracking system can reliably track the progression of TMEV-IDD for 9 months. We have also shown how this system can be utilized for longitudinal phenotyping in mice by describing useful parameters that quantify locomotion, gait and behavior.