Mouse mutants from chemically mutagenized embryonic stem cells

Area of Science:

• Genetics
• Developmental Biology
• Genomics

Background:

• Large-scale generation of mouse mutants is crucial for characterizing human gene functions globally.
• Conventional N-ethyl-N-nitrosourea (ENU) mutagenesis faces limitations in monitoring efficiency, strain variation, and requires extensive husbandry.
• New methods are needed to overcome these obstacles for efficient mouse mutant generation.

Purpose of the Study:

• To develop novel protocols for generating mouse mutants using mutagenized embryonic stem (ES) cells.
• To overcome limitations associated with conventional germ-cell mutagenesis.

Main Methods:

• Protocols were devised to generate germline chimaeric mice from embryonic stem (ES) cells treated with ethyl methanesulfonate (EMS).
• Mutation rates were assessed, with up to 1 in 1,200 mutations observed at the Hprt locus.
• Mutation spectrum analysis was performed for EMS and ICR191.

Main Results:

• Germline chimaeras were successfully generated from EMS-mutagenized ES cells.
• EMS-induced mutations were transmitted, affecting various processes including limb development, hair growth, hearing, and gametogenesis.
• The mutation spectrum induced by EMS was consistent with other mammalian cell studies.

Conclusions:

• The developed ES cell-based mutagenesis strategy offers advantages over traditional methods.
• This technology allows for shortened breeding schemes and direct screening of mutant phenotypes in ES cells or derivatives.
• It provides a powerful tool for large-scale functional genomics and the study of gene function.