Details for: CL4033031

Cell ID: CL4033031

Cell Name: diffuse bipolar 4 cell

Description: An ON diffuse bipolar cell that predominantly connects to ON parasol cells and lateral amacrine cells.

Synonyms: DB4 cell

Selected Context(s): Overall

Gene Significance Landscape

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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 diffuse bipolar 4 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 diffuse bipolar 4 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 diffuse bipolar 4 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 diffuse bipolar 4 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:  diffuse bipolar 4 cell (CL4033031)

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Nodes (Genes):
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Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
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 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 [diffuse bipolar 4 cell](/details-cell/CL4033031), or DB4 cell, is a neuronal subtype within the retina, specifically characterized as an ON diffuse bipolar cell. Its primary role involves relaying signals from photoreceptors, with predominant connections to ON parasol cells and lateral amacrine cells. Analysis of its gene expression profile reveals a highly specialized identity defined by a unique consortium of transcription factors, RNA-binding proteins, and ion channels. The high expression specificity (**`csi_z`**) of genes such as the transcriptional coregulator [CAMTA1](/details-gene/23261) and the cytoskeletal protein [DST](/details-gene/667) suggests that its function is maintained by a distinct regulatory architecture and robust structural framework, which are as defining as its specialized electrophysiological machinery. ## Key Characteristics and Function The functional identity of the [diffuse bipolar 4 cell](/details-cell/CL4033031) appears to be established through several key molecular programs, as indicated by its top specificity markers. * **Neuronal Signaling and Ion Transport:** A core feature of this cell is its specialized machinery for signal transmission. The high specificity of ion channel genes such as [TRPM1](/details-gene/4308), a known marker for ON-bipolar cells essential for the light response, confirms its described function ([Link](https://pubmed.ncbi.nlm.nih.gov/19436059/)). Additionally, the presence of [HCN1](/details-gene/348980), a hyperpolarization-activated "pacemaker" channel, and [KCNMA1](/details-gene/3778), a large-conductance calcium-activated potassium channel, suggests a complex role in modulating its membrane potential and shaping its output signal. The expression of [CADPS](/details-gene/8618), a calcium-dependent activator of secretion, further underscores its role in synaptic exocytosis. * **Transcriptional and Post-Transcriptional Regulation:** The cell's unique state is maintained by a specific set of regulatory factors. [CAMTA1](/details-gene/23261) and [LMO4](/details-gene/8543) are transcriptional regulators with high specificity, indicating they may drive the cell-type-specific gene expression program. Furthermore, a suite of highly specific RNA-binding proteins, including [PUM2](/details-gene/23369), [TNRC6B](/details-gene/23112), [SRRM4](/details-gene/84530), and [MSI2](/details-gene/124540), suggests that post-transcriptional control, such as alternative splicing and mRNA stability, is critical for fine-tuning its proteome and potentially enabling rapid, localized responses at synaptic terminals. * **Cytoskeletal Organization and Cell Adhesion:** Structural integrity and synaptic connectivity are highlighted by the high specificity of [DST](/details-gene/667), which links cytoskeletal elements, and [CADM2](/details-gene/253559), a cell adhesion molecule involved in synaptic organization. This suggests that the physical architecture of the DB4 cell and its connections within the retinal circuitry are actively maintained by a distinct set of proteins. * **Anti-Markers:** **Overall**, the genes with low or negative specificity scores are housekeeping genes or those ubiquitously expressed across many cell types. The low specificity (**`csi_z`**) for mitochondrial genes like [COX1](/details-gene/4512), [COX2](/details-gene/4513), and [ND2](/details-gene/4536), as well as for [GAPDH](/details-gene/2597), does not imply their absence. Instead, it indicates that their expression levels are not a defining feature of this cell type compared to its neighbors in the retinal microenvironment. ## Clinical Significance and Contextual Roles As the analysis is based on an **Overall** context, it is not possible to assess dynamic changes in gene significance between healthy and disease states. However, the top marker genes for the [diffuse bipolar 4 cell](/details-cell/CL4033031) have established clinical relevance, pointing to the cell's potential involvement in retinal and systemic diseases. * The high specificity of [TRPM1](/details-gene/4308) is particularly significant, as mutations in this gene are a well-known cause of autosomal recessive congenital stationary night blindness, a disorder characterized by impaired ON-bipolar cell signaling. This directly links the molecular identity of this cell type to a specific visual pathology. * [DST](/details-gene/667), the gene encoding bullous pemphigoid antigen 1, is associated with a severe autoimmune blistering skin disease, but its high specificity in this neuronal context suggests a distinct, potentially crucial role in retinal architecture that is not yet fully understood. * The tumor suppressor [PTEN](/details-gene/5728) is a notable marker, and its dysregulation is implicated in numerous cancers. Its specific expression in DB4 cells may point to a role in regulating cell survival and signaling pathways within the mature retina. * Mutations in [ATRX](/details-gene/546) cause ATR-X syndrome, a severe X-linked disorder involving intellectual disability. Its high specificity suggests that DB4 cells could be among the cell types affected by this syndrome's pathology. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The specific combination and expression of ion channels, including the canonical ON-bipolar channel [TRPM1](/details-gene/4308), the pacemaker channel [HCN1](/details-gene/348980), and the regulatory channel [KCNMA1](/details-gene/3778), work in concert to precisely shape the graded potential signal of the [diffuse bipolar 4 cell](/details-cell/CL4033031), allowing for tailored signal transmission to its specific downstream targets. * **Surprising Findings:** It is notable that a transcriptional coregulator ([CAMTA1](/details-gene/23261)) and a cytoskeletal protein ([DST](/details-gene/667)) show higher expression specificity than even the classic ON-bipolar channel [TRPM1](/details-gene/4308). This suggests that the unique identity of this cell is not solely defined by its electrophysiological function but also by a highly specific transcriptional program and structural framework. * **Testable Questions:** How does targeted inactivation of [HCN1](/details-gene/348980) or [KCNMA1](/details-gene/3778) specifically in bipolar cells affect the light-evoked responses of downstream parasol ganglion cells in a mouse model? 2. **Hypothesis:** Post-transcriptional regulation orchestrated by a unique set of RNA-binding proteins ([PUM2](/details-gene/23369), [MSI2](/details-gene/124540)) and splicing factors ([SRRM4](/details-gene/84530)) is a critical layer of control that maintains the functional proteome and enables synaptic plasticity in [diffuse bipolar 4 cells](/details-cell/CL4033031), potentially through local mRNA translation at synaptic terminals. * **Surprising Findings:** The identification of [XIST](/details-gene/7503), a long non-coding RNA central to X-chromosome inactivation, as a highly specific marker is unexpected. While it may reflect a sampling bias towards female donors, it could also imply a novel, non-canonical function for [XIST](/details-gene/7503) in the regulation of autosomal genes in this specific neuronal subtype. * **Testable Questions:** Using techniques like CLIP-seq (cross-linking immunoprecipitation sequencing) on isolated [diffuse bipolar 4 cells](/details-cell/CL4033031), what are the specific mRNA targets of [PUM2](/details-gene/23369), and do these targets encode key synaptic or signaling proteins?