Details for: CL4033027

Cell ID: CL4033027

Cell Name: diffuse bipolar 1 cell

Description: An OFF diffuse bipolar cell that makes synaptic contact with both L/M and S-cone photoreceptors and only minimal contact with rod photoreceptors.

Synonyms: DB1 bipolar cell, DB1 bipolar, DB1 cell, Diffuse Bipolar Cell Type DB1

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 1 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 1 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 1 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 1 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 1 cell (CL4033027)

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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
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 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 1 cell](/details-cell/CL4033027) (DB1) is a type of OFF bipolar neuron in the retina, primarily characterized by its function as an intermediary in the visual pathway. It receives synaptic input from both L/M-cone and S-cone photoreceptors and relays this information to downstream retinal ganglion cells. The molecular profile of the [diffuse bipolar 1 cell](/details-cell/CL4033027) is distinguished by a high expression specificity of genes involved in synaptic organization, cell adhesion, and neurotransmitter signaling. **Overall**, the top marker genes, including the transmembrane protein [NETO1](/details-gene/81832) and the cell adhesion molecule [MDGA2](/details-gene/161357), underscore its role in establishing and maintaining precise neural circuitry. The specific expression of ion channel subunits like [GRIA2](/details-gene/2891) and transcription factors such as [CAMTA1](/details-gene/23261) further suggests a tightly regulated molecular program dedicated to specialized signal processing and cellular identity within the complex architecture of the retina. ## Key Characteristics and Function The functional identity of the [diffuse bipolar 1 cell](/details-cell/CL4033027) is defined by a distinct set of highly specific gene markers, as indicated by their high Z-score based Cell Significance Index (CSI). These genes can be categorized into several key functional clusters that collectively orchestrate the cell's role in visual signal transduction. * **Synaptic Structure and Cell Adhesion:** A prominent feature of the DB1 cell is its enrichment for genes crucial to synaptic integrity and neuronal connectivity. Top markers [NETO1](/details-gene/81832) (CSI 13.39) and [MDGA2](/details-gene/161357) (CSI 13.30) are involved in nervous system development and cell-cell interactions. This is further supported by the high specificity of [NRXN3](/details-gene/9369) (Neurexin 3) and [CNTN1](/details-gene/1272) (Contactin 1), both established cell adhesion molecules vital for synaptic organization. Additionally, the high CSI for [SYT1](/details-gene/6857) (Synaptotagmin-1), a key calcium sensor for neurotransmitter release, highlights the cell's specialization in rapid, regulated synaptic transmission. * **Ionotropic Receptors and Channels:** As an OFF bipolar cell, the DB1 cell must respond to glutamate released from photoreceptors in the dark. The high specificity of [GRIA2](/details-gene/2891) (CSI 11.70), a subunit of the AMPA-type ionotropic glutamate receptor, is consistent with this role. The expression signature also points to a specialized electrophysiological profile, with high specificity for the large-conductance calcium-activated potassium channel [KCNMA1](/details-gene/3778) (CSI 11.30) and the transient receptor potential channel [TRPM1](/details-gene/4308) (CSI 9.40). The presence of [TRPM1](/details-gene/4308) is particularly noteworthy as it is canonically associated with the light response of ON bipolar cells, suggesting a potentially distinct function in this OFF cell type. * **Transcriptional and Chromatin Regulation:** The unique identity of the [diffuse bipolar 1 cell](/details-cell/CL4033027) appears to be maintained by a specific suite of regulatory proteins. The high CSI values for transcription factors like [CAMTA1](/details-gene/23261) (CSI 13.30), [ZNF292](/details-gene/23036) (CSI 12.41), and [GTF2I](/details-gene/2969) (CSI 10.63) indicate their central role in defining the cell's transcriptional program. Furthermore, the specificity of chromatin-modifying genes such as [KMT2C](/details-gene/58508), [ATRX](/details-gene/546), and [ARID1B](/details-gene/57492) suggests that the epigenetic landscape is critical for establishing and preserving this neuron's specific phenotype. * **Anti-Markers:** The analysis of least significant genes provides further insight into the cell's specialized nature. Genes encoding core components of the mitochondrial electron transport chain, such as [ND2](/details-gene/4536) (CSI -9.56), [COX3](/details-gene/4514), [COX2](/details-gene/4513), [ND3](/details-gene/4537), and [ND1](/details-gene/4535), exhibit strong negative CSI scores. This does not imply an absence of mitochondria but suggests that the expression of these essential metabolic genes is significantly less specific in DB1 cells compared to the average of other cell types. This may reflect a specialized metabolic state relative to highly active cells like photoreceptors. Similarly, ubiquitously expressed genes involved in protein degradation ([UBB](/details-gene/7314)) and RNA processing ([HNRNPA2B1](/details-gene/3181)) also show low specificity, reinforcing the distinct and specialized molecular identity of the DB1 cell. ## Clinical Significance and Contextual Roles While this analysis is based on an **Overall** context without direct comparison to a disease state, the specific gene signature of the [diffuse bipolar 1 cell](/details-cell/CL4033027) highlights several genes with known clinical relevance, suggesting potential involvement in retinopathies and other neurological disorders. The high specificity of [TRPM1](/details-gene/4308) is of major clinical interest. Mutations in [TRPM1](/details-gene/4308) are a primary cause of congenital stationary night blindness (CSNB), a disorder characterized by impaired function of the ON bipolar cell pathway ([Link](https://pubmed.ncbi.nlm.nih.gov/19436059/)). Its status as a top specific marker in an OFF bipolar cell is unexpected and may imply a broader role for this channel in retinal function, and its dysfunction could potentially contribute to more complex visual deficits than currently understood. Furthermore, several top markers are implicated in broader neurodevelopmental and neoplastic disorders. [PTEN](/details-gene/5728), a potent tumor suppressor, is a highly specific marker (CSI 9.36). While its role in post-mitotic neurons is not fully understood, it is known to regulate cell size and synaptic function. Alterations in its expression could impact neuronal health and circuit stability. Similarly, [ARID1B](/details-gene/57492) and [KMT2C](/details-gene/58508) are chromatin remodeling genes whose mutations are associated with intellectual disability syndromes, highlighting the importance of precise epigenetic regulation for neuronal function. The neuregulin gene [NRG3](/details-gene/10718), which activates the ErbB4 receptor, has been linked to schizophrenia ([Link](https://pubmed.ncbi.nlm.nih.gov/9275162/)), suggesting that signaling pathways active in this retinal neuron may be shared with those in the central nervous system implicated in psychiatric disease. The strong expression of synaptic adhesion molecules and ion channels like [GRIA2](/details-gene/2891) and [KCNMA1](/details-gene/3778) positions the DB1 cell as a potential site of pathology in diseases affecting synaptic transmission and retinal circuit integrity. Dysregulation of these genes could disrupt the faithful relay of visual information from cones, potentially contributing to the pathophysiology of various degenerative or functional retinal disorders. ## Potential Mechanisms and Research Directions 1. **Hypothesis: A unique "adhesion code" defined by a specific combination of cell surface molecules dictates the precise, diffuse connectivity of the [diffuse bipolar 1 cell](/details-cell/CL4033027) with both L/M and S-cone photoreceptors.** * **Surprising Findings:** The identification of [NETO1](/details-gene/81832) and [MDGA2](/details-gene/161357) as the top two most specific markers is unexpected. While neurexins ([NRXN3](/details-gene/9369)) are well-known synaptic organizers, the prominence of [NETO1](/details-gene/81832) (a CUB-domain containing protein) and [MDGA2](/details-gene/161357) (an immunoglobulin superfamily member) suggests a more complex and multi-faceted molecular system is required to establish the cell's characteristic wiring pattern compared to more stereotyped synaptic pairings. * **Testable Questions:** Does conditional knockout of [NETO1](/details-gene/81832) or [MDGA2](/details-gene/161357) in retinal progenitor cells during development lead to a measurable reduction in synaptic contacts or incorrect partnering with photoreceptor subtypes in the resulting DB1 cells, as assessed by electron microscopy and electroretinography? 2. **Hypothesis: In the [diffuse bipolar 1 cell](/details-cell/CL4033027), the ion channel [TRPM1](/details-gene/4308) performs a non-canonical function distinct from its established role in the ON-pathway, potentially modulating intracellular calcium homeostasis or regulating resting membrane potential to fine-tune the cell's responsiveness to glutamate.** * **Surprising Findings:** The discovery of [TRPM1](/details-gene/4308), the cardinal functional marker for ON bipolar cells, as a highly specific gene for this OFF bipolar cell type challenges the conventional bifurcation of retinal signaling pathways. It implies that key molecular components may be repurposed for different functions across seemingly opposing circuits. * **Testable Questions:** Using high-resolution immunocytochemistry or in-situ hybridization, what is the precise subcellular localization of the [TRPM1](/details-gene/4308) protein in DB1 cells? Furthermore, does pharmacologic blockade or genetic ablation of [TRPM1](/details-gene/4308) in an ex-vivo retinal preparation alter the baseline electrophysiological properties or the glutamate-evoked currents of DB1 cells, without affecting the fundamental OFF response?