Details for: CL0000836

Cell ID: CL0000836

Cell Name: promyelocyte

Description: A precursor in the granulocytic series, being a cell intermediate in development between a myeloblast and myelocyte, that has distinct nucleoli, a nuclear-to-cytoplasmic ratio of 5:1 to 3:1, and containing a few primary cytoplasmic granules. Markers for this cell are fucosyltransferase FUT4-positive, CD33-positive, integrin alpha-M-negative, low affinity immunoglobulin gamma Fc region receptor III-negative, and CD24-negative.

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 promyelocyte 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 promyelocyte. 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 promyelocyte. 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 promyelocyte. 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.
Select a context for the baseline cell.
Select a context for the target cell.
Target Cell for CSI:  promyelocyte (CL0000836)

 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 [promyelocyte](/details-cell/CL0000836) is a granulocyte precursor cell, representing an intermediate stage between a myeloblast and a myelocyte. Based on its gene significance profile, this cell is characterized by an exceptionally high level of activity in fundamental biological processes, including chromatin organization, transcription, RNA processing, and energy metabolism. The top marker genes, such as the histone variant [H2AZ1](/details-gene/3015), the chromatin-binding protein [HMGB1](/details-gene/3146), and the glycolytic enzyme [GAPDH](/details-gene/2597), suggest that the [promyelocyte](/details-cell/CL0000836) is a cellular factory, primed for rapid proliferation and the immense biosynthetic task of producing primary granule proteins required for its differentiation into mature granulocytes. ## Key Characteristics and Function The gene signature of the [promyelocyte](/details-cell/CL0000836) is dominated by genes essential for cellular infrastructure and biosynthesis, highlighting its role as a highly active, transit-amplifying cell. These markers can be grouped into several key functional clusters. * **High Metabolic Activity and Energy Production:** **Overall**, the most striking feature is the high significance of genes involved in energy production. This includes the central glycolytic gene [GAPDH](/details-gene/2597) and a remarkable number of components of the mitochondrial electron transport chain, such as [COX4I1](/details-gene/1327), [ATP5MC2](/details-gene/517), [COX7C](/details-gene/1350), [COX1](/details-gene/4512), [ATP5F1E](/details-gene/514), and [UQCRB](/details-gene/7381). This robust metabolic signature is consistent with a cell state requiring vast amounts of ATP to fuel rapid cell division and the synthesis of a large protein repertoire. * **Chromatin Remodeling and Transcriptional Regulation:** The top marker, [H2AZ1](/details-gene/3015), is a histone variant associated with transcriptionally active chromatin, suggesting a globally permissive chromatin state. This is complemented by the high significance of [HMGB1](/details-gene/3146), a non-histone architectural protein that facilitates DNA bending and access for transcription factors. The presence of general transcription factors like [BTF3](/details-gene/689) further underscores the cell's intense transcriptional activity as it executes its differentiation program. * **RNA Processing and Ribosome Biogenesis:** A large cohort of highly significant genes are involved in post-transcriptional regulation. These include multiple heterogeneous nuclear ribonucleoproteins ([HNRNPA2B1](/details-gene/3181), [HNRNPC](/details-gene/3183), [HNRNPU](/details-gene/3192), [HNRNPA1](/details-gene/3178)) critical for mRNA splicing and transport. Furthermore, the high significance of nucleolar proteins [NPM1](/details-gene/4869) and [NCL](/details-gene/4691) points to a high rate of ribosome biogenesis, a prerequisite for the massive protein synthesis required to fill the cell's characteristic primary granules. The iron-storage protein [FTL](/details-gene/2512) is also a key marker, likely reflecting the high demand for iron as a cofactor for enzymes like myeloperoxidase, a hallmark of these granules. * **Anti-Markers:** The genes with the lowest significance for [promyelocytes](/details-cell/CL0000836) are largely involved in late-stage cell cycle control and mitotic spindle formation, such as [KNL1](/details-gene/57082), [AURKA](/details-gene/6790), and [KIF11](/details-gene/3832), as well as specialized DNA repair pathways ([POLQ](/details-gene/10721)). While seemingly counterintuitive for a proliferating cell, this pattern may indicate that while proliferation is occurring, the unique identity of the [promyelocyte](/details-cell/CL0000836) is more specifically defined by its immense biosynthetic capacity rather than the mechanics of cell division, which are shared more broadly with other cycling cells. ## Clinical Significance and Contextual Roles The gene profile of the [promyelocyte](/details-cell/CL0000836) holds direct clinical relevance, particularly in the context of hematological malignancies. The [promyelocyte](/details-cell/CL0000836) is the cell of origin for Acute Promyelocytic Leukemia (APL), a subtype of Acute Myeloid Leukemia (AML). The high significance of **[NPM1](/details-gene/4869)** (Nucleophosmin 1) is particularly notable. Mutations in [NPM1](/details-gene/4869) are among the most common genetic alterations in AML, defining a distinct disease entity ([Link](https://pubmed.ncbi.nlm.nih.gov/2478125/)). Its central role in ribosome biogenesis and its high expression in normal [promyelocytes](/details-cell/CL0000836) suggest that its dysregulation is a key step in the transformation of this cell type. Similarly, **[HMGB1](/details-gene/3146)** is a damage-associated molecular pattern (DAMP) molecule that can be released by dying cells to promote inflammation. Its high expression in [promyelocytes](/details-cell/CL0000836) may implicate these cells in regulating the bone marrow microenvironment during normal hematopoiesis and potentially contributing to the inflammatory state often observed in leukemia. The general theme of high expression of genes controlling RNA processing ([HNRNPA1](/details-gene/3178), [HNRNPC](/details-gene/3183)) and chromatin structure ([H2AZ1](/details-gene/3015)) points to multiple nodes of vulnerability. The processes these genes govern are frequently hijacked during leukemogenesis to enforce a state of arrested differentiation and unchecked proliferation. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The defining signature of the [promyelocyte](/details-cell/CL0000836) reflects a state of "metabolic overdrive," where a vast network of mitochondrial and glycolytic genes is coordinately upregulated not just for proliferation, but to specifically fuel the immense energetic and substrate demands of primary granule protein synthesis and processing. * **Surprising Findings:** The sheer dominance of metabolic and protein synthesis "housekeeping" genes over classical lineage-defining transcription factors in the top marker list. This suggests that at this developmental checkpoint, the cell's identity is less defined by the factors that guide its fate and more by the massive biosynthetic machinery it has built to execute that fate. * **Testable Questions:** How does the metabolic flux of glucose and glutamine in [promyelocytes](/details-cell/CL0000836) compare to earlier myeloblasts and later myelocytes, and can this flux be directly correlated with the rate of synthesis of specific granule proteins like myeloperoxidase? 2. **Hypothesis:** The unique chromatin and RNA-processing environment of the normal [promyelocyte](/details-cell/CL0000836), marked by high levels of [H2AZ1](/details-gene/3015), [HMGB1](/details-gene/3146), and [NPM1](/details-gene/4869), creates a state of cellular plasticity that is inherently susceptible to leukemogenic transformation. These factors, essential for managing the cell's high transcriptional and translational throughput, become oncogenic dependencies when a driving mutation (e.g., PML-RARA) is acquired. * **Surprising Findings:** The rank of [H2AZ1](/details-gene/3015) as the single most significant gene. While its role in gene regulation is established ([Link](https://pubmed.ncbi.nlm.nih.gov/1697587/)), its specific function in orchestrating the promyelocytic differentiation program, and its potential role in APL pathogenesis, is less characterized than that of [NPM1](/details-gene/4869), suggesting it may be a more fundamental and overlooked aspect of this cell's biology. * **Testable Questions:** Does experimental depletion of [H2AZ1](/details-gene/3015) in normal hematopoietic progenitors block their differentiation at the [promyelocyte](/details-cell/CL0000836) stage, and does this depletion alter the sensitivity of APL cells to therapeutic agents like all-trans retinoic acid (ATRA)?