Pluripotent stem cells could self-renew and differentiate into various cells. In particular, porcine pluripotent stem cells are useful for preclinical therapy, transgenic animals, and agricultural usage. These stem cells have naïve and primed pluripotent states. Naïve pluripotent stem cells represented by mouse embryonic stem cells form chimeras after blastocyst injection. Primed pluripotent stem cells represented by mouse epiblast stem cells and human embryonic stem cells. They could not produce chimeras after blastocyst injection. Populations of embryonic stem cells are not homogenous; therefore, reporter systems are used to clarify the status of stem cells and to isolate the cells. For this reason, studies of the OCT4 reporter system have been conducted for decades. This review will discuss the naïve and primed pluripotent states and recent progress in the development of porcine OCT4 reporter systems.

ABSTRACT
INTRODUCTION
NAÏVE AND PRIMED PLURIPOTENT STATES
OCT4 REPORTER SYSTEM FOR MONITORINGPLURIPOTENCY
APPLICATION OF AN OCT4 REPORTERSYSTEM
REFERENCES

• Seung-Hun Kim(Department of Agricultural Biotechnology, Animal Biotechnology Major, and Research Institute of Agriculture and Life Science, Seoul National University, Seoul 08826, Korea)
• Chang-Kyu Lee(Department of Agricultural Biotechnology, Animal Biotechnology Major, and Research Institute of Agriculture and Life Science, Seoul National University,Designed Animal & Transplantation Research Institute, Institute of Green Bio Science and Technology, Seoul National University,) Corresponding author