Fig. 6: Lsm1 originates from both gametes and helps establish totipotency.

a Agarose gel electrophoresis of RT–PCR amplification of full-length Lsm1 mRNA from sperm and oocytes. Representative images from 3 biological replicates. b Agarose gel electrophoresis of RT–PCR detection of Lsm1 mRNA from cytoplasm and nucleus of somatic cells. Representative images from 3 biological replicates. c Lsm1 mRNA levels between IVF and SCNT zygotes as quantified by qPCR. The statistical data are expressed as mean ± SEM, *p < 0.05 (p = 0.0409) by two-sided Student’s t test for each comparison. Each reaction for qPCR analysis contains 3 biological replicates, with each replicate from 50 zygotes. d MajSat RNA level between IVF and SCNT zygotes as quantified by qPCR. The statistical data are expressed as mean ± SEM, *p < 0.05 (p = 0.0137) by two-sided Student’s t test for each comparison. Each reaction for qPCR analysis contains 3 biological replicates, with each replicate from 50 zygotes. e, f Quantification of SCNT embryo developmental competence in response to Lsm1 overexpression (Lsm1_OE). Images of 2-cell embryos and blastocysts for the Ctrl and Lsm1_OE groups (e) and statistics for blastocyst rates (f) were represented. Scale bars, 100 µm. Representative images from 3 biological replicates, with each replicate originating from ~35 embryos. The statistical data are expressed as mean ± SEM, *p < 0.05 (p = 0.0428) by two-sided Student’s t test for each comparison. Each treatment contains 3 biological replicates, with each replicate contains ~35 embryos. g Proposed model for the regulation of nonequilibrium pronuclear histone variants and concomitant asymmetric histone modifications by LSM1-induced major satellite RNA decay.