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Updated: Jul 3, 2026
Efficient Generation of hiPSC Neural Lineage Specific Knockin Reporters Using the CRISPR/Cas9 and Cas9 Double Nickase System
Published on: May 28, 2015
A cytokine screen using CRISPR-Cas9 knock-in reporter pig iPS cells reveals that Activin A regulates NANOG
Junjun Xu1,2, Zheng Zheng2, Xuguang Du1,2
1State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Background:
NANOG functions as the gateway for the generation of pluripotent stem cells (PSCs) in mice and humans. NANOG is a transcription factor highly expressed in pig pre-implantation embryos, indicating that it is a conserved pluripotency-associated factor. However, pig NANOG reporter PSCs have yet to be established, and the regulation of pluripotency by NANOG is not fully understood in this animal.
Methods:
In this study, pig NANOG tdTomato knock-in reporter positive PC-iPS cells were established using CRISPR/Cas9. The resulting cell line was treated with several cytokines and their corresponding inhibitors to identify pathways that regulate NANOG expression. The pathways examined were LIF (leukemia inhibitory factor)/IL6 (interleukin 6)-STAT3, FGF (fibroblast growth factor)/ERK, IGF1 (insulin-like growth factor 1)/PIP3 (phosphoinositide 3-kinase)-AKT, Activin A/SMAD, and BMP4 (bone morphogenetic proteins)/SMAD.
Results:
Our experiments showed that the Activin A/SMAD pathway is directly associated with activation of NANOG expression in the pig, as is also the case in mice and humans. Activin A directly regulates the expression of pig NANOG via SMAD2/3; inhibition of this pathway by SB431542 resulted in inhibition of NANOG expression.
Conclusions:
Our results show that Activin A plays an important regulatory role in NANOG-mediated pluripotency in pig iPS cells. Activin A treatment may be therefore an effective method for de novo derivation of authentic embryonic stem cells (ESCs) from pig pre-implantation embryos.
