Oct-4 expression in pluripotent cells of the rhesus monkey.
The POU (Pit-Oct-Unc)-domain transcription factor, Oct-4, has become a useful marker of pluripotency in the mouse. It is found exclusively in mouse preimplantation-stage embryos after embryonic genome activation and is a characteristic of mouse embryonic stem (ES) cells, and its absence in knockout mice precludes inner cell mass (ICM) formation in blastocysts. Expression of Oct-4 has also been associated with pluripotency in primate cells. Here, we undertook a systematic study of Oct-4 expression in rhesus macaque preimplantation embryos produced by intracytoplasmic sperm injection and in ES cells before and after exposure to differentiating conditions in vitro. We also evaluated Oct-4 expression as a means of monitoring the extent of reprogramming following somatic cell nuclear transfer. Oct-4 was detected by reverse transcription-polymerase chain reaction and immunocytochemistry with a monoclonal antibody. Monkey pronuclear-stage zygotes and cleaving embryos up to the 8-cell stage showed no detectable Oct-4. Nuclear staining for Oct-4 first became obvious at the 16-cell stage, and a strong signal was observed in morula and compact morula stages. Both ICM and trophectodermal cell nuclei of monkey early blastocysts were positive for Oct-4. However, the signal was diminished in trophectodermal cells of expanded blastocysts, whereas expression remained high in ICM nuclei. Similar to the mouse, hatched monkey blastocysts showed strong Oct-4 expression in the ICM, with no detectable signal in the trophectoderm. Undifferentiated monkey ES cells derived from the ICM of in vitro-produced blastocysts expressed Oct-4, consistent with their pluripotent nature, whereas ES cell differentiation was associated with signal loss. Therefore, Oct-4 expression in the monkey, as in the mouse, provides a useful marker for pluripotency after activation of the embryonic genome. Finally, the observed lack or abnormal expression of Oct-4 in monkey nuclear transfer embryos suggests inadequate nuclear reprogramming.
Mitalipov
Shoukhrat M
SM
Oregon National Primate Research Center, Beaverton, Oregon 97006, USA.
Kuo
Hung-Chih
HC
Hennebold
Jon D
JD
Wolf
Don P
DP
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D019976:Cloning, Organism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004624:Embryo Transfer; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008253:Macaca mulatta; D051379:Mice; D008815:Mice, Inbred Strains; D009028:Morula; D050814:Octamer Transcription Factor-3; D009865:Oocytes / Q000502:physiology; D039904:Pluripotent Stem Cells / Q000502:physiology*; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D014157:Transcription Factors