The mouse gcd2 mutation causes primordial germ cell depletion.

Area of Science:

• Reproductive biology
• Developmental genetics
• Mammalian reproduction

Background:

• The germ cell depletion 2 (gcd2) mutation in mice leads to infertility.
• This infertility stems from germ cell depletion occurring early in embryonic development, after germ cell migration to the gonads.

Purpose of the Study:

• To investigate the genetic basis of the gcd2 mutation.
• To understand the requirements for germ cell proliferation and survival in the embryonic gonad.

Main Methods:

• Chemical induction of recessive mutation in mice.
• Phenotypic analysis of infertility and germ cell depletion.
• Genetic mapping to a 1Mb region on Chromosome 2.
• Sequencing of candidate genes within the critical region.
• BAC rescue experiments for candidate genes.

Main Results:

• The gcd2 mutation causes germ cell depletion by embryonic day 11.5.
• Sterility phenotype is incompletely penetrant and strain-dependent, ranging from 37% to nearly 100%.
• Genetic mapping identified a critical region on Chr 2, but sequencing coding regions and BAC rescue failed to identify the causative mutation.

Conclusions:

• The gcd2 mutation impacts germ cell proliferation/survival after arrival in the embryonic gonad.
• The causative mutation may lie in non-coding sequences or affect genes outside the mapped region.
• Further investigation is needed to identify the precise genetic cause of gcd2-induced infertility.