Stem cell pluripotency and transcription factor Oct4

Abstract

Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21 st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.

The culture and establishment of embryonic germ (EG) cell lines from Chinese mini swine

“…Oct-4 is a transcription factor that has been considered as a marker for the totipotency of mammalian cells [23]. During mouse development, oct-4 gene is expressed only in pluripotent embryonic cells, such as blastomeres, ICM of blastocysts, epiblasts, primordial germ cells and most of germ cells.…”

Differential Role for Transcription Factor Oct4 Nucleocytoplasmic Dynamics in Somatic Cell Reprogramming and Self-renewal of Embryonic Stem Cells

“…Indeed, a decrease in Oct4 expression to Ͻ50% of normal levels triggers cell differentiation toward the trophectoderm lineage, whereas a 50% increase in expression promotes cell differentiation into mesoderm or endoderm (6,15). Although numerous studies have shown that the expression level of Oct4 is transcriptionally regulated, either positively or negatively, by various factors (16), the post-translational regulation of Oct4 is not well characterized. However, there is evidence that Oct4 is modified by ubiquitination (17), sumoylation (18), and phosphorylation (19 -21).…”

Identification of a putative transactivation domain in human Nanog

“…The capability for self-renewal and the pluripotency of embryonic stem (ES) cells seem to be under the control of multiple transcriptional factors (Pesce and Scholer, 2001;Pan et al, 2002) in the presence of leukemia inhibitory factor (LIF). However, LIF is not sufficient to prevent differentiation and maintain the pluripotency of human ES cells (Niwa et al, 2000;Reubinoff et al, 2000;Cavaleri and Scholer, 2002).…”