Completely ES cell-derived mice produced by tetraploid complementation using inner cell mass (ICM) deficient...

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Reproductive Biology

Background:

• Tetraploid complementation is a key technique for generating mice from embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs).
• The precise mechanisms governing tetraploid complementation and the extent of ESC contribution remain incompletely understood.
• It is not definitively proven whether this method can yield entirely ESC-derived mice.

Purpose of the Study:

• To investigate the underlying mechanisms of tetraploid complementation.
• To determine if completely ESC-derived mice can be produced using this method.
• To classify tetraploid blastocysts and assess their potential for generating ESC-derived offspring.

Main Methods:

• Classification of mouse tetraploid blastocysts into two types based on inner cell mass (ICM) presence (type a) or absence (type b).
• Derivation of ESC lines from type a and type b blastocysts.
• Utilization of type a and type b blastocysts for tetraploid complementation experiments.
• Analysis of resulting mice for chimerism and ESC contribution.

Main Results:

• Type a blastocysts (with ICM) readily yielded ESC lines, suggesting retained pluripotency.
• Type b blastocysts (without ICM) showed very low potential for ESC derivation, indicating loss of pluripotency.
• Complementation with type a blastocysts resulted in some 2n/4n chimeric mice.
• Complementation with type b blastocysts exclusively produced completely ESC-derived mice, often with abdominal hernias.

Conclusions:

• Completely ESC-derived mice can be generated using ICM-deficient tetraploid blastocysts.
• The formation of ICM-deficient blastocysts is crucial for achieving full ESC contribution.
• This study provides evidence that the exclusion of tetraploid cells in chimeras is linked to ICM-deficient blastocyst formation.