Analysis Tools
mortality/aging
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• no homozygous pups are born from heterozygous intercrosses
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• although the % of homozygous embryos follows Mendelian ratios at the late 4-cell stage, a reduced number of embryos is observed as early as the 8-cell stage and no blastocysts are obtained from an intercross of heterozygous mice
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reproductive system
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• heterozygous intercrosses result in significantly smaller litter sizes than matings of heterozygous mice with wild-type controls
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embryo
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• homozygous embryos arrest at the morula stage, prior to blastocyst formation, due to impaired protein translation
• at E2.5-E3.25, arrested embryos show a concomitant decrease in the protein levels of CDX2 (a trophoblast marker) and pluripotency factors (NANOG and OCT4), indicating a failure in the first cell fate decision
• microinjection of Znhit3 cRNA at the late 1-cell stage partially rescues the morula arrest phenotype, allowing embryos to progress to the blastocyst stage albeit with fewer blastomeres, smaller blastocoels and smaller size than control embryos
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• when zygotes are flushed after intercross of heterozygous mice and cultured in vitro, ~25% of embryos appear already degenerated or retain morula morphology at E4.25
• after heterozygous intercross and in vitro culture, single embryo genotyping at E4.0 shows that 8 of 9 homozygous embryos remain as morulae whereas heterozygous or wild-type embryos progress to blastocysts
• after in vivo mating of heterozygous mice, homozygous embryos flushed from the uterus at E4.0 fail to progress beyond the morula stage and appear degenerated
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• after in vivo mating of heterozygous mice, homozygous embryos flushed from the uterus at E4.0 are arrested at the morula stage and fail to form a blastocoel
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homeostasis/metabolism
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• homozygous embryos show decreased snoRNA and rRNA abundance and slightly increased intron retention, leading to defects in ribosome assembly and function and a severe reduction in nascent protein synthesis as early as the 8-cell stage
• failure to translate proteins leads to increased degradation of non-complexed RNAs (including rRNA and snoRNA) and a reduction in key transcription factors (OCT4, NANOG, and CDX2) required for the first cell fate commitment, causing developmental arrest
• microinjection of Znhit3 cRNA at the late 1-cell stage fails to fully restore the protein translation machinery and NANOG and CDX2 abundance to the same extent as in control embryos
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cellular
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• homozygous embryos show decreased snoRNA and rRNA abundance and slightly increased intron retention, leading to defects in ribosome assembly and function and a severe reduction in nascent protein synthesis as early as the 8-cell stage
• failure to translate proteins leads to increased degradation of non-complexed RNAs (including rRNA and snoRNA) and a reduction in key transcription factors (OCT4, NANOG, and CDX2) required for the first cell fate commitment, causing developmental arrest
• microinjection of Znhit3 cRNA at the late 1-cell stage fails to fully restore the protein translation machinery and NANOG and CDX2 abundance to the same extent as in control embryos
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