Conserved POU binding DNA sites in the Sox2 upstream enhancer regulate gene expression in embryonic and neural stem cells.
The Sox2 transcription factor is expressed early in the stem cells of the blastocyst inner cell mass and, later, in neural stem cells. We previously identified a Sox2 5'-regulatory region directing transgene expression to the inner cell mass and, later, to neural stem cells and precursors of the forebrain. Here, we identify a core enhancer element able to specify transgene expression in forebrain neural precursors of mouse embryos, and we show that the same core element efficiently activates transcription in inner cell mass-derived embryonic stem (ES) cells. Mutation of POU factor binding sites, able to recognize the neural factors Brn1 and Brn2, shows that these sites contribute to transgene activity in neural cells. The same sites are also essential for activity in ES cells, where they bind different members of the POU family, including Oct4, as shown by gel shift assays and chromatin immunoprecipitation with anti-Oct4 antibodies. Our findings indicate a role for the same POU binding motifs in Sox2 transgene regulation in both ES and neural precursor cells. Oct4 might play a role in the regulation of Sox2 in ES (inner cell mass) cells and, possibly, at the transition between inner cell mass and neural cells, before recruitment of neural POU factors such as Brn1 and Brn2.
Catena
Raffaella
R
Department of Biotechnology and Biosciences, University of Milano-Bicocca, piazza della Scienza 2, Milano 20126, Italy.
Tiveron
Cecilia
C
Ronchi
Antonella
A
Porta
Silvia
S
Ferri
Anna
A
Tatangelo
Laura
L
Cavallaro
Maurizio
M
Favaro
Rebecca
R
Ottolenghi
Sergio
S
Reinbold
Rolland
R
Schöler
Hans
H
Nicolis
Silvia K
SK
D024506:5' Flanking Region; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D024002:HMGB Proteins; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology; D009687:Nuclear Proteins / Q000235:genetics*; D050814:Octamer Transcription Factor-3; D055748:SOXB1 Transcription Factors; D013234:Stem Cells / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D004268:DNA-Binding Proteins; D024002:HMGB Proteins; D009687:Nuclear Proteins; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D014157:Transcription Factors