Details for: CL4033029

Cell ID: CL4033029

Cell Name: diffuse bipolar 3a cell

Description: An OFF calbindin-positive bipolar cell that has a large dendritic field and stratifies narrowly close to the middle of the inner plexiform layer. Its axon terminal is characterized by regularly branching and varicose processes resembling beads on a string. Most of DB3a contacts with cones are triad-associated.

Synonyms: DB3 cell, DB3a cell

Selected Context(s): Overall

Gene Significance Landscape

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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 3a 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 3a 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 3a 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 3a 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.

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Target Cell for CSI:  diffuse bipolar 3a cell (CL4033029)

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Edges (Interactions):
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## Summary The [diffuse bipolar 3a cell](/details-cell/CL4033029), also known as the DB3a cell, is a distinct type of OFF bipolar cell within the retina. Its morphology is characterized by a large dendritic field receiving input primarily from cones and an axon that stratifies narrowly near the middle of the inner plexiform layer. Gene significance analysis, based on expression specificity (**`csi_z`**), reveals a molecular profile dominated by genes involved in neuronal development, synaptic organization, and transcriptional regulation. Top markers such as [MDGA2](/details-gene/161357), [NETO1](/details-gene/81832), and [HCN1](/details-gene/348980) underscore its identity as a highly specialized neuron equipped for precise signal processing and integration within the visual circuitry. The data suggest its unique function is defined by a specific repertoire of cell adhesion molecules, ion channels, and a dedicated epigenetic and post-transcriptional regulatory program. ## Key Characteristics and Function **Overall**, the gene signature of the [diffuse bipolar 3a cell](/details-cell/CL4033029) points to a neuron with highly specialized roles in synaptic communication, signal modulation, and cellular identity maintenance. The top markers can be grouped into several key functional clusters: * **Synaptic Adhesion and Neuronal Structure:** A prominent group of markers is involved in cell-cell recognition and the formation of the neural architecture. These include [MDGA2](/details-gene/161357), a cell adhesion molecule involved in nervous system development; [NETO1](/details-gene/81832), an auxiliary subunit for kainate receptors that modulates synaptic transmission; and [NRXN3](/details-gene/9369), a neurexin critical for synapse formation and function. The high specificity of [ADAM23](/details-gene/8745) and [NTM](/details-gene/50863) further reinforces the importance of a precise molecular code for establishing and maintaining its specific connections within the retinal layers. * **Ion Channel Activity and Signal Transduction:** The cell exhibits a unique complement of ion channel and receptor genes, suggesting a sophisticated capacity for electrical signal processing. Key markers include [HCN1](/details-gene/348980), a hyperpolarization-activated cation channel crucial for setting neuronal rhythmicity; [KCNIP4](/details-gene/80333), a modulator of A-type potassium channels; [KCNMA1](/details-gene/3778), a large-conductance calcium-activated potassium channel; and [GABRB2](/details-gene/2561), a subunit of the GABA-A receptor. The presence of [GABRB2](/details-gene/2561) strongly indicates that this cell receives inhibitory inputs, likely from amacrine cells, which would be critical for shaping its receptive field properties and enhancing visual contrast. * **Transcriptional and Post-Transcriptional Regulation:** A surprisingly high number of top markers are involved in regulating gene expression, highlighting a robust internal program for maintaining its specialized state. These include chromatin modifiers like [KMT2E](/details-gene/55904) and [KANSL1](/details-gene/284058), and the cohesin-loading factor [NIPBL](/details-gene/25836), suggesting a distinct epigenetic landscape. Furthermore, the high specificity of RNA-binding proteins and splicing factors like [DDX17](/details-gene/10521), [HNRNPC](/details-gene/3183), and the neuron-specific splicing regulator [SRRM4](/details-gene/84530) implies that alternative splicing is a critical mechanism for generating the precise protein isoforms required for DB3a cell function. * **Anti-Markers:** The least significant genes provide clues about what the cell is not. The strong negative CSI scores for numerous core mitochondrial genes involved in the electron transport chain (e.g., [ND5](/details-gene/4540), [COX3](/details-gene/4514), [COX7A2](/details-gene/1347)) are noteworthy. This may suggest that the [diffuse bipolar 3a cell](/details-cell/CL4033029) has a comparatively lower or more specialized metabolic profile than other retinal neurons. Additionally, the low significance of ubiquitously expressed housekeeping genes like [TPT1](/details-gene/7178) and [CFL1](/details-gene/1072) emphasizes its highly differentiated and specialized nature. ## Clinical Significance and Contextual Roles While this analysis is based on a general **Overall** context without direct disease comparison, the specific gene markers for the [diffuse bipolar 3a cell](/details-cell/CL4033029) have significant clinical implications. Dysfunction of genes that define this cell's identity could contribute to retinal diseases. For instance, [HCN1](/details-gene/348980) channels are essential for proper signaling in photoreceptors and other neurons; mutations can be associated with retinal disorders. The high specificity of the GABA-A receptor subunit [GABRB2](/details-gene/2561) suggests that disruptions in inhibitory signaling to this specific bipolar cell type could alter visual processing, potentially contributing to disorders involving abnormal contrast sensitivity or visual field defects. Furthermore, the prominence of genes implicated in broad neurodevelopmental disorders underscores their critical role in establishing this cell type. [NIPBL](/details-gene/25836) is the primary gene mutated in Cornelia de Lange syndrome ([Link](https://pubmed.ncbi.nlm.nih.gov/15146185/)), a complex developmental disorder. Its high specificity here suggests that the retinal circuitry may be subtly or overtly affected in such conditions. Similarly, genes like [NRG3](/details-gene/10718) ([Link](https://pubmed.ncbi.nlm.nih.gov/9275162/)) and [NRXN3](/details-gene/9369) have been linked to neuropsychiatric conditions, highlighting the shared molecular machinery between retinal and central nervous system development and function. Therefore, the [diffuse bipolar 3a cell](/details-cell/CL4033029) may serve as a valuable model for understanding how defects in these fundamental neurodevelopmental genes manifest at the level of a single, identifiable neuron. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The functional identity of the [diffuse bipolar 3a cell](/details-cell/CL4033029) is sculpted by a unique, cell-type-specific alternative splicing program, orchestrated by factors such as [SRRM4](/details-gene/84530). This program likely generates specific isoforms of key synaptic proteins ([NRXN3](/details-gene/9369)), receptors ([GABRB2](/details-gene/2561)), and ion channels ([KCNMA1](/details-gene/3778)), which are essential for its precise stratification, synaptic connectivity, and signal-processing characteristics. * **Surprising Findings:** The high specificity scores for broadly acting chromatin remodelers ([KMT2E](/details-gene/55904), [KANSL1](/details-gene/284058)) and the cohesin complex component [NIPBL](/details-gene/25836) in a terminally differentiated neuron is unexpected. It suggests that the stable identity of this cell requires continuous, active maintenance of a unique epigenetic state, rather than being a developmentally "locked-in" phenomenon. * **Testable Questions:** Does conditional knockout of [SRRM4](/details-gene/84530) in the developing retina alter the axonal stratification or synaptic partner selection of DB3a cells? Furthermore, can long-read sequencing of RNA from isolated DB3a cells identify novel splice variants of its top marker genes compared to other bipolar cell types? 2. **Hypothesis:** The [diffuse bipolar 3a cell](/details-cell/CL4033029) functions as a critical node for signal integration and temporal filtering within the OFF visual pathway, primarily through its distinct combination of ion channels. The [HCN1](/details-gene/348980) channel, in particular, may play a crucial role in shaping the cell's response kinetics to light offsets, while inhibitory input via [GABRB2](/details-gene/2561)-containing receptors provides lateral inhibition that sharpens its spatial receptive field. * **Surprising Findings:** The consistent negative CSI scores for multiple core components of the mitochondrial respiratory chain are counterintuitive for a neuron, which is typically a high-energy-demand cell type. This might indicate a specialized metabolic adaptation, perhaps a greater reliance on glycolysis or a metabolic coupling with adjacent Müller glia, to support its specific signaling functions. * **Testable Questions:** How do selective pharmacological blockers of HCN channels (e.g., ZD7288) and GABA-A receptors (e.g., bicuculline) alter the light-evoked voltage responses of DB3a cells, as measured by in situ patch-clamp electrophysiology in retinal slices?