CR1
complement C3b/C4b receptor 1 (Knops blood group) | CD35, KN

This gene is a member of the receptors of complement activation (RCA) family and is located in the 'cluster RCA' region of chromosome 1. The genome is polymorphic at this locus with allele-specific splice variants encoding different isoforms, based on the presence/absence of long homologous repeats (LHRs). The gene encodes a monomeric single-pass type I membrane glycoprotein found on erythrocytes, leukocytes, glomerular podocytes, and splenic follicular dendritic cells. The Knops blood group system is a system of antigens located on this protein. The protein mediates cellular binding to particles and immune complexes that have activated complement. Decreases in expression of this protein and/or mutations in this gene have been associated with gallbladder carcinomas, mesangiocapillary glomerulonephritis, systemic lupus erythematosus, sarcoidosis and Alzheimer's disease. Mutations in this gene have also been associated with a reduction in Plasmodium falciparum rosetting, conferring protection against severe malaria. [provided by RefSeq, May 2020]

Biological processes 48 terms
ATP export (GO:1904669)T cell mediated immunity (GO:0002456)cell surface (GO:0009986)complement activation (GO:0006956)complement activation, alternative pathway (GO:0006957)complement activation, alternative pathway (GO:0006957)complement binding (GO:0001848)complement component C3b binding (GO:0001851)complement component C3b receptor activity (GO:0004877)complement component C4b binding (GO:0001855)complement component C4b receptor activity (GO:0001861)complement receptor activity (GO:0004875)complement receptor mediated signaling pathway (GO:0002430)cytoskeleton (GO:0005856)extracellular exosome (GO:0070062)extracellular region (GO:0005576)ficolin-1-rich granule membrane (GO:0101003)glomerulus development (GO:0032835)immune complex clearance (GO:0002434)immune complex clearance by erythrocytes (GO:0002435)membrane (GO:0016020)negative regulation of T cell proliferation (GO:0042130)negative regulation of activation of membrane attack complex (GO:0001971)negative regulation of complement activation (GO:0045916)negative regulation of complement activation, alternative pathway (GO:0045957)negative regulation of complement activation, classical pathway (GO:0045959)negative regulation of complement activation, classical pathway (GO:0045959)negative regulation of complement-dependent cytotoxicity (GO:1903660)negative regulation of immunoglobulin production (GO:0002638)negative regulation of interleukin-2 production (GO:0032703)negative regulation of plasma cell differentiation (GO:1900099)negative regulation of serine-type endopeptidase activity (GO:1900004)negative regulation of type II interferon production (GO:0032689)organ or tissue specific immune response (GO:0002251)plasma membrane (GO:0005886)plasma membrane (GO:0005886)plasma membrane (GO:0005886)plasma membrane (GO:0005886)plasma membrane organization (GO:0007009)plasma membrane raft (GO:0044853)positive regulation of activation of membrane attack complex (GO:0001970)positive regulation of cell population proliferation (GO:0008284)positive regulation of regulatory T cell differentiation (GO:0045591)positive regulation of serine-type endopeptidase activity (GO:1900005)protein binding (GO:0005515)regulation of complement activation (GO:0030449)regulation of complement-dependent cytotoxicity (GO:1903659)secretory granule membrane (GO:0030667)
Expression (TPM)
CR1 — as a Regulated Gene

TFs regulating CR1 0 TFs

Transcription factors with Perturb-seq knockdown data for CR1. The Binding column indicates whether any binding evidence exists for this TF–gene pair (ChIP-seq or motif footprint peaks). The Mean coef is the average Perturb-seq regression coefficient across active gRNAs (positive = CR1 upregulated upon KD; negative = downregulated). The Outlier column indicates whether this gene is in the top or bottom 5% of all TF knockdown effects.

Data: Effect:
TF Mean coef Binding Outlier TF→Gene link

Elements linked to CR1

Open chromatin peaks (ATAC-seq) in the genomic neighbourhood of CR1, linked by TSS proximity or chromatin conformation (Multiome / HiCAR). Each element overlaps at least one TF ChIP-seq binding site — the TFs column shows how many distinct TFs bind that element.

Accessibility Element Dist. to TSS Link type TFs
chr1:207,495,767–207,496,784 at TSS At TSS 161
chr1:207,499,586–207,499,784 3.2 kb Proximal (<10kb) 181

Genome Browser

Genomic view of the CR1 locus showing ATAC-seq accessibility and RNA-seq expression across the ESC → DE time course, together with TF binding peaks and element-to-TSS loop connections.

chr1:207,485,767 – 207,509,784
Proximal 1 kb Distal 10 kb Multiome HiCAR ATAC-seq RNA-seq