Details for: CL0000750

Cell ID: CL0000750

Cell Name: OFF-bipolar cell

Description: A bipolar neuron found in the retina and having connections with photoreceptors cells and neurons in the outer half of the inner plexiform layer. These cells depolarize in response to light to dark transition.

Selected Context(s): Overall

Gene Significance Landscape

Display Options
Score:
Display
Genes

Contexts:

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 OFF-bipolar 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 OFF-bipolar 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 OFF-bipolar 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 OFF-bipolar 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:  OFF-bipolar cell (CL0000750)

 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.

Loading network (please wait)...

## Summary The [OFF-bipolar cell](/details-cell/CL0000750) is a specialized retinal neuron that depolarizes in response to light-to-dark transitions, playing a critical role in processing the "OFF" visual pathway. The gene significance profile suggests this cell is a metabolic powerhouse, characterized by the uniquely high expression of numerous genes involved in mitochondrial electron transport and ATP synthesis. This indicates a high energetic demand required to sustain its continuous synaptic signaling. Furthermore, top markers related to cell cycle control, such as [CCNI](/details-gene/10983), and transcriptional regulation, like [BTG1](/details-gene/694), point towards potentially novel, non-proliferative functions in maintaining neuronal homeostasis and plasticity within the retinal microenvironment. ## Key Characteristics and Function **Overall**, the gene expression landscape of the [OFF-bipolar cell](/details-cell/CL0000750) is dominated by genes reflecting intense metabolic and biosynthetic activity, consistent with its role as a key signal-transducing neuron. * **Exceptional Metabolic Activity:** A striking feature is the significant overrepresentation of genes encoding subunits of the mitochondrial respiratory chain. This includes multiple components of Complex III ([UQCRB](/details-gene/7381)), Complex IV ([COX6C](/details-gene/1345), [COX7A2](/details-gene/1347), [COX5B](/details-gene/1329), [COX4I1](/details-gene/1327), [COX7C](/details-gene/1350)), Complex V ([ATP5MG](/details-gene/10632), [ATP5MC2](/details-gene/517)), and Complex I ([NDUFA4](/details-gene/4697)). The high specificity score (`csi_z`) for this entire suite of genes, alongside the glycolytic enzyme [GAPDH](/details-gene/2597), strongly suggests that a high capacity for aerobic respiration is a defining characteristic of this cell type, necessary to fuel the constant ion pumping required for graded potential signaling. * **Robust Protein and RNA Homeostasis:** The cell appears to maintain a highly active system for protein synthesis, processing, and quality control. High significance scores for [SRP14](/details-gene/6727), a component of the signal recognition particle essential for protein targeting, and [SRSF5](/details-gene/6430), an mRNA splicing factor, underscore this theme. The prominence of RNA-binding proteins like [CIRBP](/details-gene/1153) and [PNISR](/details-gene/25957) may indicate a role for post-transcriptional regulation in response to visual stimuli. * **Stress Response and Cellular Maintenance:** The cell expresses high levels of genes critical for managing metabolic byproducts and cellular stress. This includes [SOD1](/details-gene/6647), which detoxifies superoxide radicals, and the ferritin components [FTH1](/details-gene/2495) and [FTL](/details-gene/2512), which manage iron homeostasis. This machinery is likely crucial for mitigating the oxidative stress generated by its high mitochondrial activity. * **Atypical Regulatory Gene Expression:** The top marker, the cyclin [CCNI](/details-gene/10983), is unexpected in a terminally differentiated neuron. Its isolation from the human brain, as noted in a 1995 publication ([Link](https://doi.org/10.1006/excr.1995.1406)), suggests a conserved, non-canonical role in the nervous system. Paired with the high significance of [BTG1](/details-gene/694), an antiproliferative gene, this may point to a specialized regulatory axis controlling neuronal function or survival rather than cell division. * **Distinct Lineage Identity:** The anti-marker profile helps define what the [OFF-bipolar cell](/details-cell/CL0000750) is not. The low significance of photoreceptor-specific genes like [RBP3](/details-gene/5949) and [PDE6A](/details-gene/5145) confirms its identity as a distinct interneuron, separate from the photoreceptors it connects with. Similarly, the negative CSI for [B2M](/details-gene/567) is consistent with the immune-privileged status of neurons, suggesting low levels of MHC class I presentation. ## Clinical Significance and Contextual Roles **Overall**, the gene profile highlights the [OFF-bipolar cell's](/details-cell/CL0000750) vulnerability to metabolic and oxidative insults, making it relevant to a range of neurodegenerative and retinal diseases. The profound dependence on mitochondrial function suggests that these cells may be particularly susceptible to mitochondrial DNA mutations or systemic metabolic disorders that impair aerobic respiration, potentially contributing to retinal pathologies. The high significance of [SOD1](/details-gene/6647), a gene whose mutations are famously linked to amyotrophic lateral sclerosis (ALS), underscores the cell's reliance on robust antioxidant defenses. Dysregulation of this system could be a contributing factor in retinal neurodegeneration. Furthermore, the high expression of [RTN4](/details-gene/57142), also known as Nogo, is clinically significant. As a well-characterized inhibitor of neurite outgrowth ([Link](https://doi.org/10.1038/35000287)), its prominent role in [OFF-bipolar cells](/details-cell/CL0000750) may be crucial for maintaining the precise and stable synaptic architecture of the retina. This also implies it could be a key barrier to axonal regeneration following retinal injury. The protein ubiquitination pathway, highlighted by the significance of [UBB](/details-gene/7314) and [SKP1](/details-gene/6500), is essential for protein quality control, and its dysfunction is a hallmark of many neurodegenerative diseases. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The identity and function of the [OFF-bipolar cell](/details-cell/CL0000750) are primarily dictated by an exceptionally high, constitutively active metabolic program centered on mitochondrial respiration. This state is required to sustain the continuous neurotransmission that signals darkness and makes the cell a point of high vulnerability in retinal diseases associated with metabolic or oxidative stress. * **Surprising Findings:** It is not merely a few metabolic genes that are highly specific, but a broad and coordinated signature spanning multiple complexes of the electron transport chain ([UQCRB](/details-gene/7381), [COX6C](/details-gene/1345), [COX5B](/details-gene/1329), etc.). This suggests that the entire respiratory apparatus, rather than a single component, serves as a defining molecular feature of this cell. * **Testable Questions:** Using retinal organoids or ex vivo retinal slices, does pharmacologic inhibition of specific respiratory complexes (e.g., Complex IV with sodium azide) lead to a more rapid and severe loss of synaptic function (as measured by patch-clamp recordings) in [OFF-bipolar cells](/details-cell/CL0000750) compared to other retinal neurons like [ON-bipolar cells](/details-cell/CL0000749)? 2. **Hypothesis:** The top-ranking specificity marker, the cyclin [CCNI](/details-gene/10983), and the antiproliferative factor [BTG1](/details-gene/694), operate outside their canonical cell cycle roles to form a regulatory node that governs synaptic plasticity or metabolic scaling in response to chronic changes in visual input. * **Surprising Findings:** The single most specific gene marker for a post-mitotic neuron is a cyclin. This paradoxical finding strongly implicates a novel, non-proliferative function, potentially related to the regulation of CDK kinases that have known roles in synaptic function and neuronal gene expression. The co-expression of the antiproliferative gene [BTG1](/details-gene/694) may serve as a complementary check to prevent re-entry into the cell cycle. * **Testable Questions:** Does conditional knockout of [CCNI](/details-gene/10983) specifically in retinal bipolar cells alter their dendritic morphology, the expression of synaptic proteins at their terminals, or their electrophysiological response properties after prolonged periods of light or dark adaptation?