Three LIF-dependent signatures and gene clusters with atypical expression profiles, identified by transcriptome studies in mouse ES cells and early derivatives.
BACKGROUND
Mouse embryonic stem (ES) cells remain pluripotent in vitro when grown in the presence of the cytokine Leukaemia Inhibitory Factor (LIF). Identification of LIF targets and of genes regulating the transition between pluripotent and early differentiated cells is a critical step for understanding the control of ES cell pluripotency.


RESULTS
By gene profiling studies carried out with mRNAs from ES cells and their early derivatives treated or not with LIF, we have identified i) LIF-dependent genes, highly expressed in pluripotent cells, whose expression level decreases sharply upon LIF withdrawal [Pluri genes], ii) LIF induced genes [Lifind genes] whose expression is differentially regulated depending upon cell context and iii) genes specific to the reversible or irreversible committed states. In addition, by hierarchical gene clustering, we have identified, among eight independent gene clusters, two atypical groups of genes, whose expression level was highly modulated in committed cells only. Computer based analyses led to the characterization of different sub-types of Pluri and Lifind genes, and revealed their differential modulation by Oct4 or Nanog master genes. Individual knock down of a selection of Pluri and Lifind genes leads to weak changes in the expression of early differentiation markers, in cell growth conditions in which these master genes are still expressed.


CONCLUSIONS
We have identified different sets of LIF-regulated genes depending upon the cell state (reversible or irreversible commitment), which allowed us to present a novel global view of LIF responses. We are also reporting on the identification of genes whose expression is strictly regulated during the commitment step. Furthermore, our studies identify sub-networks of genes with a restricted expression in pluripotent ES cells, whose down regulation occurs while the master knot (composed of OCT4, SOX2 and NANOG) is still expressed and which might be down-regulated together for driving cells towards differentiation.
Trouillas
Marina
M
Université Bordeaux, Bordeaux, France.
Saucourt
Claire
C
Guillotin
Bertrand
B
Gauthereau
Xavier
X
Ding
Li
L
Buchholz
Frank
F
Doss
Michael Xavier
MX
Sachinidis
Agapios
A
Hescheler
Jurgen
J
Hummel
Oliver
O
Huebner
Norbert
N
Kolde
Raivo
R
Vilo
Jaak
J
Schulz
Herbert
H
Boeuf
Hélène
H
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D016000:Cluster Analysis; D053595:Embryonic Stem Cells / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D053605:Leukemia Inhibitory Factor / Q000378:metabolism*; D051379:Mice / Q000235:genetics*; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D039904:Pluripotent Stem Cells / Q000378:metabolism
D018398:Homeodomain Proteins; D053605:Leukemia Inhibitory Factor; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse