Porcine OTX2 was found to be highly activated in porcine iPS cells (piPSCs) that 
were reported by different laboratories worldwide. To reveal the regulatory 
function of OTX2 in porcine reprogrammed cells, we screened porcine miRNA-seq 
databases and found two miRNAs, miR-1343 and miR-545, that could specifically 
bind to 3'UTR of OTX2 and suppress endogenous OTX2 expression in piPSCs. 
Knockdown of OTX2 by miR-1343 and miR-545 could significantly increase the 
expression of SOX2 and ESRRB, but did not alter the expressions of OCT4 and 
KLF4, and improve the pluripotency of piPSCs. The promoter-based assays showed 
that OTX2 potentially bound to the promoter region of SOX2 and ESRRB and 
suppressed their expression. On the other hand, SOX2 could interact with OTX2 
promoter. Ectopic expression of SOX2 could significantly decrease OTX2 promoter 
activity, showing that there is a negative feedback loop between SOX2 and OTX2. 
Additionally, SOX2 and ESRRB significantly stimulated miR-1343 expression in 
piPSCs, but OTX2 down regulated the expression of miR-1343 in either direct or 
indirect manners. In summary, this study demonstrates that there is a regulatory 
network mediated by miR-1343, in which downregulation of OTX2 by miR-1343 can 
elevate the expression of pluripotent genes that were then sustain the 
pluripotency of piPSCs.