Fatemeh Mirzadeh Azad - Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
Mahshid Malak ootian - Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences,Tehran, Iran
Seyed Javad Mowla - Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran

OCT4 is the major regulator of pluripotency in embryonic stem cells and its association withtumorigenesis, cellular stress response, and homeostatic multifactorial diseases have been recently reported. Toserve the versatility in its function, OCT4 generates several transcript variants which their expression levels aretightly regulated through different mechanisms. PSORS1C3 is a long non-coding RNA with overlapping genomiclocation with OCT4 gene. Here, we investigated the effect of PSORS1C3 overexpression on OCT4 expression indifferent cell lines. Our data revealed that ectopic expression of PSORS1C3 did not affect OCT4 transcriptsabundance in NT2 cells, as a model of pluripotent cells. However, in HEK293T cells, PSORS1C3 overexpressionled to an increase in OCT4B as a homeostatic isoform and a decrease in OCT4A transcript level. We also observedthat manipulating PSORS1C3 in HeLa cells, as a model of epithelial carcinoma line, caused an upregulation inOCT4A, OCT4C which could regulate stemness and proliferation and OCT4B transcripts at different time points.Our findings indicated that PSORS1C3 could affect the expression level of OCT4 spliced variants, according totheir functions and the cells molecular context as well as genetic background. Considering these diverse regulatoryeffects and co-expression of OCT4 and PSORS1C3 in some cell lines, it is safe to consider PSORS1C3 as amodulator of OCT4 expression in non-pluripotent cells and in association with homeostatic pathways.

OCT4, PSORS1C3, expression regulation, lncRNA