Transcriptional properties of human NANOG1 and NANOG2 in acute leukemic cells.
Transcripts of NANOG and OCT4 have been recently identified in human t(4;11) leukemia and in a model system expressing both t(4;11) fusion proteins. Moreover, downstream target genes of NANOG/OCT4/SOX2 were shown to be transcriptionally activated. However, the NANOG1 gene belongs to a gene family, including a gene tandem duplication (named NANOG2 or NANOGP1) and several pseudogenes (NANOGP2-P11). Thus, it was unclear which of the NANOG family members were transcribed in t(4;11) leukemia cells. 5'-RACE experiments revealed novel 5'-exons of NANOG1 and NANOG2, which could give rise to the expression of two different NANOG1 and three different NANOG2 protein variants. Moreover, a novel PCR-based method was established that allows distinguishing between transcripts deriving from NANOG1, NANOG2 and all other NANOG pseudogenes (P2-P11). By applying this method, we were able to demonstrate that human hematopoietic stem cells and different leukemic cells transcribe NANOG2. Furthermore, we functionally tested NANOG1 and NANOG2 protein variants by recombinant expression in 293 cells. These studies revealed that NANOG1 and NANOG2 protein variants are functionally equivalent and activate a regulatory circuit that activates specific stem cell genes. Therefore, we pose the hypothesis that the transcriptional activation of NANOG2 represents a 'gain-of-stem cell function' in acute leukemia.
Eberle
Irina
I
Institute of Pharmaceutical Biology/DCAL/ZAFES/CEF, Goethe-University, Biocenter, Max-von-Laue-Str. 9, 60438 Frankfurt/Main, Germany.
Pless
Birgit
B
Braun
Miriam
M
Dingermann
Theo
T
Marschalek
Rolf
R
D000208:Acute Disease; D017398:Alternative Splicing; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D020869:Gene Expression Profiling; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase; D018398:Homeodomain Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007938:Leukemia / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D051788:Myeloid-Lymphoid Leukemia Protein / Q000235:genetics; D000071317:Nanog Homeobox Protein; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D014178:Translocation, Genetic
D018398:Homeodomain Proteins; C497422:KMT2A protein, human; C486780:NANOG protein, human; C552728:NANOGP1 protein, human; D000071317:Nanog Homeobox Protein; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase