Genetic analysis of the role of the reprogramming gene LIN-28 in human embryonic stem cells.
LIN-28 is a gene recently shown to be involved in the conversion of somatic cells to induced pluripotent stem cells. We have previously shown that LIN-28 is highly expressed in human embryonic stem cells (HESCs); however, its role in these cells has not been investigated. We now show that, like OCT4, SOX2, and NANOG, LIN-28 is downregulated during differentiation of HESCs into embryoid bodies. In addition, we investigate the role of LIN-28 in HESCs by manipulation of its expression levels. LIN-28 overexpression impairs the ability of cells to grow at clonal densities, due to increased differentiation and decreased cell division. Analysis of cell differentiation under these conditions revealed that it is mostly towards the extraembryonic endoderm lineage. Moreover, we show that, during early mouse development, high levels of Lin-28 are also observed in the extraembryonic endoderm, and therefore it seems that, both in vitro and in vivo, high levels of LIN-28 may specify an extraembryonic endoderm fate. However, LIN-28 seems dispensable for self-renewal of HESCs; its downregulation neither impairs HESC proliferation nor leads to their differentiation. Thus, LIN-28 does not seem to be involved in the self-renewal of HESCs, but rather seems to be involved in their decision to switch from self-renewal to differentiation.
Darr
Henia
H
Department of Genetics, Institute of Life Sciences, The Hebrew University, Jerusalem, Israel.
Benvenisty
Nissim
N
D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C488352:Lin-28 protein, mouse; C000715187:Lin28A protein, human; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins