Details for: CL0000050

Cell ID: CL0000050

Cell Name: megakaryocyte-erythroid progenitor cell

Description: MEPs are reportedly CD19-negative, CD34-negative, CD45RA-negative, CD110-positive, CD117-positive, and SCA1-negative and reportedly express the transcription factors GATA-1 and NF-E2.

Synonyms: CFU-EM, CFU-MegE, MEP, Meg/E progenitor, colony forming unit erythroid megakaryocyte, megakaryocyte/erythrocyte progenitor, megakaryocyte/erythroid progenitor cell

Selected Context(s): Overall

Gene Significance Landscape

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Score:
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Genes

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Cell Significance Index (CSI) is uniquely calculated to reveal cell-specific gene markers. More info here

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for megakaryocyte-erythroid progenitor cell within the selected context(s).

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for megakaryocyte-erythroid progenitor cell. Higher scores indicate a stronger, more significant difference in expression.
(Previously described as "Fold Change", but now represents Cliff's Delta × –log10(p).)

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for megakaryocyte-erythroid progenitor cell. Higher scores indicate a stronger, more significant difference in expression.
Average CSI: csi sum / gene count
Cell network configuration

This network visualizes key genes for megakaryocyte-erythroid progenitor cell. It primarily includes:
1. Top genes highly significant for this cell (Num. Top Cell Genes - based on the 'Min. CSI' setting).
2. Any additional specific 'Context Genes' you add below.
The final network is a combined view. Choose an Interaction Source (pathways or protein interactions) and optionally compare CSI scores with a Baseline Cell Type.

Maximum number of selected genes.
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Select a context for the target cell.
Target Cell for CSI:  megakaryocyte-erythroid progenitor cell (CL0000050)

 Legend
Nodes (Genes):
 Query Gene
Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
 Very High
 High
 Medium
 Low
 Very Low
 N/A or Not Sig.
Edges (Interactions):
 STRING (Protein-Protein)
 ONTOLOGY (Shared Pathway)
 Colors vary by pathway category; default arrow applies.

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## Summary The [megakaryocyte-erythroid progenitor cell](/details-cell/CL0000050) (MEP) is a bipotent hematopoietic progenitor responsible for generating both megakaryocytes and erythrocytes. As described, it is characterized by the absence of markers like CD19, CD34, and CD45RA, and the expression of transcription factors such as GATA-1 and NF-E2. Gene significance analysis reveals that **Overall**, the MEP's identity is defined not by classic lineage-specific transcription factors but by an exceptionally high and specific expression of genes involved in fundamental cellular processes. These include extensive RNA processing machinery ([HNRNPA2B1](/details-gene/3181), [HNRNPC](/details-gene/3183)), high metabolic activity, and chromatin organization ([HMGB1](/details-gene/3146)). This molecular signature suggests a cell in a state of high metabolic readiness, actively remodeling its transcriptome and epigenome to poise itself for rapid proliferation and commitment to two distinct, terminally differentiated lineages. ## Key Characteristics and Function Analysis of top marker genes, ranked by expression specificity (`csi_z`), highlights several core functional themes that define the MEP. * **RNA Processing and Splicing Hub:** A dominant feature of the MEP is the highly significant expression of multiple heterogeneous nuclear ribonucleoproteins (hnRNPs), including [HNRNPA2B1](/details-gene/3181), [HNRNPC](/details-gene/3183), [HNRNPDL](/details-gene/9987), [HNRNPA1](/details-gene/3178), and [HNRNPA3](/details-gene/220988). This large suite of RNA-binding proteins points to post-transcriptional regulation, particularly mRNA splicing and stability, as a central mechanism governing MEP function. This intense RNA processing activity is likely critical for managing the bifurcation of gene expression programs required for megakaryocytic versus erythroid differentiation. * **High Metabolic and Biosynthetic Activity:** The cell exhibits a strong signature of high energy demand and protein synthesis. This is indicated by the specific expression of genes central to glycolysis ([GAPDH](/details-gene/2597)) and mitochondrial respiration ([COX4I1](/details-gene/1327), [ATP5MC2](/details-gene/517), [UQCRB](/details-gene/7381)). Concurrently, genes essential for ribosome biogenesis ([NPM1](/details-gene/4869), [NCL](/details-gene/4691)) and protein turnover ([UBB](/details-gene/7314)) are top markers, consistent with a progenitor preparing for the massive production of lineage-specific proteins, such as hemoglobin in erythrocytes and granules in megakaryocytes. * **Chromatin Organization and Transcriptional Readiness:** The top marker, [HMGB1](/details-gene/3146), is a non-histone chromosomal protein crucial for DNA bending and chromatin structure ([Link](https://pubmed.ncbi.nlm.nih.gov/2922262/)). Its prominence, along with the high significance of the general transcription factor [BTF3](/details-gene/689) and histone variants [H3-3A](/details-gene/3020) and [H3-3B](/details-gene/3021), underscores the dynamic state of the MEP's chromatin. This suggests active epigenetic remodeling is underway to establish the appropriate transcriptional landscape for lineage commitment. * **Priming for Iron Homeostasis:** A notable characteristic is the highly specific expression of both ferritin heavy chain ([FTH1](/details-gene/2495)) and light chain ([FTL](/details-gene/2512)). Ferritin is the primary intracellular iron storage protein. The high significance of these genes in a progenitor state strongly suggests that MEPs are pre-programmed to manage iron, a critical requirement for the subsequent development of iron-hungry erythroblasts for hemoglobin synthesis. The profile of anti-markers further refines the identity of the MEP. The low significance of genes like [HOXB4](/details-gene/3214), which is associated with hematopoietic stem cell self-renewal, is consistent with the MEP being a committed progenitor rather than a stem cell. Similarly, the lack of significance for mature lineage markers such as [GP1BA](/details-gene/2811) (platelet glycoprotein Ib alpha) confirms its undifferentiated state, positioned upstream of terminal megakaryocyte development. ## Clinical Significance and Contextual Roles The gene signature of the [megakaryocyte-erythroid progenitor cell](/details-cell/CL0000050) provides insights into its role in normal hematopoiesis and potential dysregulation in disease. The dominance of genes involved in core cellular machinery (RNA splicing, metabolism, ribosome biogenesis) suggests that perturbations in these fundamental processes could severely impact MEP function, leading to cytopenias or contributing to myelodysplastic syndromes (MDS) and leukemias. For instance, [NPM1](/details-gene/4869) (Nucleophosmin 1) is a highly significant marker involved in ribosome biogenesis and genome stability. Mutations in [NPM1](/details-gene/4869) are among the most common genetic alterations in acute myeloid leukemia (AML), highlighting the importance of its proper function in hematopoietic progenitors. While the provided data is from a general context, the high specificity of [NPM1](/details-gene/4869) in MEPs suggests this cell type could be particularly vulnerable to oncogenic transformation following [NPM1](/details-gene/4869) mutation. Furthermore, the top marker [HMGB1](/details-gene/3146) is a well-known damage-associated molecular pattern (DAMP) molecule that, when released from cells, can trigger inflammation. Its high and specific expression within MEPs may indicate a role in sensing or responding to stress in the bone marrow microenvironment. In pathological states such as bone marrow failure or inflammation-driven hematologic disorders, dysregulation of [HMGB1](/details-gene/3146) in MEPs could contribute to the pathology by linking cellular stress to inflammatory signaling. The observation that [HMGB1](/details-gene/3146) expression is elevated in gastrointestinal adenocarcinomas suggests its role in cellular proliferation and differentiation is context-dependent and may be implicated in cancer biology ([Link](https://doi.org/10.1002/(sici)1097-0215(19970220)74:1%3C1::aid-ijc1%3E3.0.co;2-6)). ## Potential Mechanisms and Research Directions 1. **Hypothesis: MEP lineage commitment is primarily orchestrated at the post-transcriptional level by a specific consortium of hnRNPs.** The data show an extraordinary enrichment for RNA-binding proteins, particularly hnRNPs ([HNRNPA2B1](/details-gene/3181), [HNRNPC](/details-gene/3183), [HNRNPA1](/details-gene/3178), etc.), as defining markers. This suggests that the decision to become a megakaryocyte versus an erythrocyte may be critically dependent on alternative splicing and/or mRNA stabilization events controlled by these factors, which fine-tune the output from master transcription factors like GATA-1. * **Surprising Findings:** The overwhelming significance of RNA processing machinery, compared to the expected prominence of lineage-defining transcription factors, is a notable finding. This implies that for MEPs, the control of pre-existing transcripts might be a more specific and defining activity than the initiation of new transcription at this precise developmental stage. * **Testable Questions:** Does targeted depletion of a top-ranked hnRNP, such as [HNRNPA2B1](/details-gene/3181), in primary MEPs using CRISPR-Cas9 or shRNA alter the ratio of megakaryocytes to erythrocytes generated in *in vitro* differentiation assays? Furthermore, what are the specific mRNA targets of [HNRNPA2B1](/details-gene/3181) in MEPs, as identified by techniques like CLIP-seq? 2. **Hypothesis: MEPs utilize HMGB1 and ferritin not only for internal housekeeping but also to sense and modulate the bone marrow niche.** The top marker, [HMGB1](/details-gene/3146), is a potent alarmin when released, while ferritin ([FTH1](/details-gene/2495)/[FTL](/details-gene/2512)) also has extracellular signaling functions and is central to managing iron, a potential source of oxidative stress. We propose that MEPs are primed to respond to niche stressors (e.g., inflammation, iron dysregulation) by potentially releasing these factors, thereby influencing their own fate and the function of surrounding cells. This positions MEPs as active participants in the feedback loops that govern emergency hematopoiesis. * **Surprising Findings:** The identification of [HMGB1](/details-gene/3146), a protein primarily studied in the context of cell death and inflammation, as the most specific marker of a healthy progenitor cell is unexpected. This suggests it has a novel, highly specific homeostatic role within MEPs, perhaps in maintaining a specific chromatin architecture necessary for lineage poising, which is distinct from its function as an extracellular alarmin. * **Testable Questions:** Does hematopoietic stress (e.g., treatment with 5-fluorouracil or lipopolysaccharide) induce the secretion of [HMGB1](/details-gene/3146) or ferritin from MEPs? If so, does this conditioned media subsequently influence the differentiation trajectory of fresh, unstressed MEPs?