Methods for modulating embryonic stem cell differentiation
Described herein is Zscan4, a gene exhibiting 2-cell embryonic stage and embryonic stem cell specific expression. Identification of nine Zscan4 co-expressed genes is also described. Inhibition of Zscan4 expression inhibits the 2-cell to 4-cell embryonic transition and prevents blastocyst implantation, expansion and outgrowth. Provided herein are methods of inhibiting differentiation of a stem cell, promoting blastocyst outgrowth of embryonic stem cells and identifying a subpopulation of stem cells expressing Zscan4. Further described is the identification of Trim43 as a gene exhibiting morula-specific expression. Also provided are isolated expression vectors comprising a Zscan4 promoter, or a Trim43 promoter operably linked to a heterologous polypeptide and uses thereof. Further provided are transgenic animals comprising transgenes encoding marker proteins operably linked to Zscan4 and Trim43 promoters.
1. An in vitro method of identifying a subpopulation of cultured human or mouse embryonic stem (ES) cells expressing Zscan4, comprising:
(a) transfecting a population of mouse or human ES cells with an expression vector comprising a Zscan4c promoter operably linked to a nucleotide sequence encoding a reporter, wherein the Zscan4c promoter is selected from group consisting of the nucleic acid sequence as set forth in nucleotides (i) 1-2540 of SEQ ID NO: 28, (ii) 1-2643 of SEQ ID NO: 28, (iii) 1-3250 of SEQ ID NO: 28 and (iv) 1-3347 of SEQ ID NO: 28; and
(b) identifying a subpopulation of cells that expresses the reporter gene indicating Zscan-4 is expressed in the subpopulation of stem cells.
2. The method of claim 1 , wherein the expression vector consists of the nucleotide sequence as set forth in SEQ ID NO: 28.
3. The method of claim 1 , wherein the reporter gene encodes a marker, enzyme, or fluorescent protein.
4. The method of claim 1 , wherein the expression vector is a viral vector.
5. The method of claim 1 , wherein the expression vector is a plasmid vector.
6. The method of claim 1 , wherein the population of embryonic stem cells are mouse embryonic stem cells.
7. The method of claim 1 , wherein the population of embryonic stem cells are human embryonic stem cells.