SWR: an inbred strain suitable for generating transgenic mice

Area of Science:

• Animal Models
• Genetics
• Reproductive Biology

Background:

• Transgenic mouse generation is typically more efficient with F2 hybrid embryos than inbred strains.
• C57BL/6 background hybrids are common, but specific research goals may require different strains, like DBA/1 for rheumatoid arthritis models.
• Identifying suitable inbred strains for efficient transgenic production is crucial for model development.

Purpose of the Study:

• To evaluate the suitability of the SWR mouse strain and its F1 hybrids for generating transgenic mice.
• To compare the SWR strain's reproductive and embryological characteristics with established strains for transgenesis.
• To assess the efficiency of generating transgenic founders using SWR and its hybrids.

Main Methods:

• Microinjection of alpha and beta T-cell receptor (TCR) chain gene constructs into embryos from DBA/1, SWR, (DBA/1 x SWR)F1, and (SWR x DBA/1)F1 strains.
• Assessment of ovulation rates, oocyte quality, pronuclear size and visibility, and resistance to lysis post-injection.
• Determination of DNA-positive founder generation efficiency.

Main Results:

• SWR female mice exhibit prolific ovulation and oocyte numbers comparable to (C57BL/6 x C3H)F1 hybrids.
• SWR and (SWR x DBA/1)F1 embryos display large, prominent pronuclei, indicative of high quality.
• Transgenic founder generation efficiency in SWR and (SWR x DBA/1)F1 embryos is comparable to (C57BL6 x C3H)F2 embryos.

Conclusions:

• The SWR mouse strain is a highly suitable inbred strain for transgene propagation, similar to the FVB strain.
• SWR mice possess favorable genetic characteristics and high ovulation rates, making them valuable for creating transgenic models.
• This study identifies SWR as a robust alternative for efficient transgenic mouse production.