Global transcription analysis of immature avian erythrocytic progenitors: from self-renewal to differentiation

Abstract

The molecular mechanisms regulating the cell fate decision between self-renewal and differentiation/apoptosis in stem and progenitor cells are poorly understood. Here, we report the first comprehensive identification of genes potentially involved in the switch from self-renewal toward differentiation of primary, non-immortalized erythroid avian progenitor cells (T2EC cells). We used the Serial Analysis of Gene Expression (SAGE) technique in order to identify and quantify the genome fraction functionally active in a self-renewing versus a differentiating cell population. We generated two SAGE libraries and sequenced a total of 37 589 tags, thereby obtaining the first transcriptional profile characterization of a chicken cell. Tag identification was performed using a new relational database (Identitag) developed in the laboratory, which allowed a highly satisfactory level of identification. Among 123 differentially expressed genes, 11 were investigated further and for nine of them the differential expression was subsequently confirmed by real-time PCR. The comparison of tag abundance between the two libraries revealed that only a small fraction of transcripts was differentially expressed. The analysis of their functions argue against a prominent role for a master switch in T2EC cells decision-making, but are in favor of a critical role for coordinated small variations in a relatively small number of genes that can lead to essential cellular identity changes.

Identitag, a relational database for SAGE tag identification and interspecies comparison of SAGE libraries

“…It played a key role for allowing biological interpretation of the SAGE libraries obtained from normal chicken erythroid progenitor cells and allowed us to better understand the changes underlying the self-renewal versus differentiation-making process in these cells [13]. Among the identifications provided by Identitag, a few were investigated further and the vast majority of these identifications were subsequently confirmed by real-time PCR [13].…”

“…It played a key role for allowing biological interpretation of the SAGE libraries obtained from normal chicken erythroid progenitor cells and allowed us to better understand the changes underlying the self-renewal versus differentiation-making process in these cells [13]. Among the identifications provided by Identitag, a few were investigated further and the vast majority of these identifications were subsequently confirmed by real-time PCR [13]. Identitag has also been successfully used for tag-to-gene mapping in Bombyx mori (J. Briolay et al, in preparation).Identitag is currently in use to identify human tags from SAGE libraries generated in order to investigate the molecular basis underlying the self-renewal versus differentiation decision-making process in human cells.…”

“…So far in chicken Identitag we have stored four different libraries generated from normal chicken immature erythroid progenitors called T2ECs [12]. The first two libraries were generated from self-renewing T2EC cells and from T2EC cells induced to differentiate for 24 hours respectively [13]. The last two libraries have been generated from T2EC cells treated with two inhibitors of the MEK-1 signaling pathway which is important for maintaining self-renewal (S. Dazy et al, in preparation).…”

Single-Cell-Based Analysis Highlights a Surge in Cell-to-Cell Molecular Variability Preceding Irreversible Commitment in a Differentiation Process

“…The primary cause for differentiation is therefore known and relies upon change in the information carried by the extracellular environment. The differentiation process in those cells has been previously analyzed at the population level [33–35]. …”

Cell Modelling of Hematopoiesis

“…Indeed, it has been shown (see A stem cell can divide into either two other stem cells to renew the initial density in case of blood renewal, or one stem cell and one of the three cell types detailed above. [11,12]) that some progenitor cells can be self renewable under hormone stimulations such as cortisol. We do not take this into account here but we are currently working on it.…”