The POU5F1P1 pseudogene encodes a putative protein similar to POU5F1 isoform 1

POU5F1, which encodes a transcriptional factor, has two alternatively spliced transcripts, 1 and 2, as well as six pseudogenes. Transcript 1 is considered to be a key regulator of cellular pluripotency and self-renewal. The POU5F1 pseudogene, POU5F1P1 on 8q24, encodes a protein with 95% homology with the isoform 1 of POU5F1. It is located 15 kbp downstream of the SNP rs6983267, which is strongly associated with an increased risk of prostate and colon cancer, and within the amplified region in a variety of human malignancies. The previous finding of expressed sequence tags suggests that POU5F1P1 can be expressed. We showed that a putative POU5F1P1 protein is localized in the nucleus, acts as a transcriptional activator and regulates the expression in a similar way to the POU5F1 isoform 1. However, POU5F1P1 was a weaker activator than isoform 1 of POU5F1, possibly due to the amino acid substitutions.