*4.4. Statistical Analysis*

Data were analyzed by Student's *t*-test and presented as means ± standard deviation (SD). A *p* value < 0.05 was considered statistically significant.

**Supplementary Materials:** Supplementary Materials can be found at http://www.mdpi.com/1422-0067/21/19/7235/ s1. Figure S1: Uterine horns with E13.5 embryos in pregnant Stab1/2 dKO mice, Figure S2: Images of unevenly sized embryos or undefined tissue in pregnant Stab1/2 dKO mice compared to normal-sized embryo and placenta of pregnant WT mice at E17.5, Figure S3: Images of the uteri or E17.5 embryos in WT and Stab1/2 dKO females and the number of viable implantation sites, Figure S4: Pedigree and the number of pups generated by crossing between male and female mice with Stab1 heterozygous and Stab2 knockout genotypes.

**Author Contributions:** S.-Y.K., S.-Y.P., I.-S.K., and J.-E.K. designed the study; S.-Y.K., E.-H.L., E.N.K., and W.-C.S. prepared the samples and performed experiments; E.N.K., Y.H.K., S.-Y.P., I.-S.K., and J.-E.K. analyzed the data; and S.-Y.K., Y.H.K., and J.-E.K. wrote the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2016R1A2B4010043, 2019R1A2C1003398).

**Conflicts of Interest:** The authors declare no conflict of interest.
