Details for: CL0009010

Cell ID: CL0009010

Cell Name: transit amplifying cell

Description: Transit-amplifying cells (TACs) are an undifferentiated population in transition between stem cells and differentiated cells.

Synonyms: TAC, TACs, transient amplifying cell, transit-amplifying cell, transit amplifying 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 transit amplifying 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 transit amplifying 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 transit amplifying 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 transit amplifying 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.
Select a context for the baseline cell.
Select a context for the target cell.
Target Cell for CSI:  transit amplifying cell (CL0009010)

 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 [transit amplifying cell](/details-cell/CL0009010) (TAC) is a progenitor population that serves as an intermediary between stem cells and their terminally differentiated progeny. Based on its gene significance profile, the defining characteristic of this cell type is an exceptionally high and specific expression of genes involved in mitochondrial energy production. This suggests that TACs are in a state of intense metabolic activity, primarily fueled by oxidative phosphorylation, which is likely essential to support their hallmark function of rapid proliferation and subsequent differentiation. ## Key Characteristics and Function The molecular identity of the [transit amplifying cell](/details-cell/CL0009010) is overwhelmingly dominated by genes related to bioenergetics and cellular proliferation. * **High-Energy Metabolism via Oxidative Phosphorylation:** **Overall**, the most significant marker genes are almost exclusively components of the mitochondrial electron transport chain and ATP synthase complex. This includes multiple subunits of cytochrome c oxidase ([COX7C](/details-gene/1350), [COX1](/details-gene/4512), [COX4I1](/details-gene/1327), [COX2](/details-gene/4513)), NADH dehydrogenase ([ND2](/details-gene/4536), [ND4](/details-gene/4538)), cytochrome b ([CYTB](/details-gene/4519)), and ATP synthase ([ATP5MG](/details-gene/10632), [ATP5F1B](/details-gene/506), [ATP6](/details-gene/4508), [ATP5MC2](/details-gene/517)). The high Z-scores for these genes indicate that this intense mitochondrial activity is a highly specific and defining feature of TACs compared to other cell types. This is further supported by the high significance of [SLC25A6](/details-gene/293), an ADP/ATP translocase essential for exporting mitochondrial ATP. * **Support for High Metabolic Rate:** The high significance of ferritin heavy and light chains ([FTH1](/details-gene/2495) and [FTL](/details-gene/2512)) is consistent with the need for iron, a critical cofactor for the heme groups within the electron transport chain cytochromes. Furthermore, the prominence of [GSTP1](/details-gene/2950), a glutathione S-transferase, suggests a robust system for managing the oxidative stress and reactive oxygen species that are natural byproducts of high-level oxidative phosphorylation. * **Active Proliferation and Protein Synthesis:** As expected for a rapidly dividing population, TACs show significant expression of genes involved in protein synthesis and cytoskeletal dynamics. Key markers include the translation elongation factor [EEF1B2](/details-gene/1933), the poly(A)-binding protein [PABPC1](/details-gene/26986), and the RNA-binding protein [HNRNPA2B1](/details-gene/3181), all pointing to active translation and mRNA processing. Concurrently, the significance of [CFL1](/details-gene/1072) (cofilin) and [MYL6](/details-gene/4637) (myosin light chain) indicates dynamic cytoskeletal remodeling, a prerequisite for cell division. * **Lack of Lineage Specialization:** The anti-markers provide strong evidence for the undifferentiated state of TACs. The low significance of genes associated with terminally differentiated functions, such as digestive enzymes ([SI](/details-gene/6476)), mucins ([MUC3A](/details-gene/4584)), specialized transporters ([SLC9A2](/details-gene/6549)), and specific immune receptors ([IL17RB](/details-gene/55540)), confirms that these cells have not yet committed to a specific functional lineage. ## Clinical Significance and Contextual Roles The unique metabolic profile of [transit amplifying cells](/details-cell/CL0009010) positions them at the center of tissue homeostasis and various pathological processes. Their role as rapidly proliferating progenitors makes them a likely cell of origin for many forms of cancer, where the machinery for rapid cell division is dysregulated. The intense reliance on oxidative phosphorylation could represent a metabolic vulnerability. Therapies targeting mitochondrial function might selectively impact hyperproliferative disorders derived from TACs. The high significance of [GSTP1](/details-gene/2950), which is involved in detoxification, suggests that these cells possess a strong defense mechanism against xenobiotics and oxidative damage. This may contribute to therapeutic resistance in cancers originating from this cell population. Similarly, the high expression of ferritin ([FTH1](/details-gene/2495), [FTL](/details-gene/2512)) indicates a central role in managing iron metabolism within their tissue niche, a process that is frequently dysregulated in inflammatory diseases and cancer. Although the available data is limited to an **Overall** context, this metabolic and proliferative signature is fundamental to understanding their potential roles in both regenerative processes and disease initiation. ## Potential Mechanisms and Research Directions 1. **Hypothesis: The extreme oxidative phosphorylation (OXPHOS) activity of TACs is a primary driver of their proliferative capacity and a key regulator of their tissue niche.** * **Surprising Findings:** The degree to which mitochondrial genes define the TAC signature is striking. It suggests that their metabolic state is not merely permissive for proliferation but may be an instructive part of their identity, potentially influencing neighboring cells through the release of metabolites or reactive oxygen species (ROS). The co-expression of the antioxidant enzyme [GSTP1](/details-gene/2950) supports the idea that these cells are adapted to manage a high level of endogenous oxidative stress. * **Testable Questions:** How does selective inhibition of mitochondrial complex I (e.g., via metformin or rotenone) affect the proliferation rate and differentiation potential of TACs in comparison to their quiescent stem cell precursors and terminally differentiated daughters? 2. **Hypothesis: TACs are maintained in a state of high translational readiness, enabling the rapid synthesis of lineage-specific proteins upon receiving differentiation signals.** * **Surprising Findings:** The high significance of genes involved in mRNA stability ([PABPC1](/details-gene/26986)), processing ([HNRNPA2B1](/details-gene/3181)), and translation elongation ([EEF1B2](/details-gene/1933)) is on par with some of the core metabolic markers. This suggests that the cellular machinery for protein production is not just a downstream consequence of proliferation but a co-regulated, defining feature of the "transit" state, primed for rapid functional changes. * **Testable Questions:** Using ribosome profiling (Ribo-seq), can we identify specific mRNAs that are pre-loaded onto ribosomes but translationally repressed in TACs, and are these mRNAs rapidly translated upon exposure to differentiation-inducing cytokines or growth factors?