CIITA

CIITA is a human gene which encodes a protein called the class II, major histocompatibility complex, transactivator.^[5] Mutations in this gene are responsible for the bare lymphocyte syndrome in which the immune system is severely compromised and cannot effectively fight infection.^[5] Chromosomal rearrangement of CIITA is involved in the pathogenesis of Hodgkin lymphoma and primary mediastinal B cell lymphoma.^[6]

CIITA
Identifiers
Aliases	CIITA, C2TA, CIITAIV, MHC2TA, NLRA, class II, major histocompatibility complex, transactivator, class II major histocompatibility complex transactivator
External IDs	OMIM: 600005; MGI: 108445; HomoloGene: 207; GeneCards: CIITA; OMA:CIITA - orthologs
Gene location (Human) Chr. Chromosome 16 (human)[1] Band 16p13.13 Start 10,866,222 bp[1] End 10,943,021 bp[1]
Gene location (Mouse) Chr. Chromosome 16 (mouse)[2] Band 16|16 A1 Start 10,297,923 bp[2] End 10,346,282 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in monocyte granulocyte appendix spleen lymph node sural nerve gallbladder upper lobe of left lung blood apex of heart Top expressed in mesenteric lymph nodes spleen blood thymus lumbar subsegment of spinal cord subcutaneous adipose tissue duodenum morula right kidney lip More reference expression data BioGPS More reference expression data
Gene ontology Molecular function transferase activity DNA binding nucleotide binding transcription coactivator activity GTP binding kinase activity protein C-terminus binding protein binding acyltransferase activity ATP binding protein-containing complex binding Cellular component PML body nucleoplasm nucleus Biological process positive regulation of MHC class II biosynthetic process regulation of transcription, DNA-templated response to interferon-gamma phosphorylation interferon-gamma-mediated signaling pathway response to antibiotic negative regulation of transcription by RNA polymerase II transcription, DNA-templated positive regulation of transcription, DNA-templated immune response negative regulation of transcription, DNA-templated positive regulation of MHC class I biosynthetic process negative regulation of collagen biosynthetic process positive regulation of transcription by RNA polymerase II inflammatory response Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 4261 12265 Ensembl ENSG00000179583 ENSMUSG00000022504 UniProt P33076 P79621 RefSeq (mRNA) NM_000246 NM_001286402 NM_001286403 NM_001379330 NM_001379331 NM_001379332 NM_001379333 NM_001379334 NM_001243760 NM_001243761 NM_007575 NM_001302618 NM_001302619 RefSeq (protein) NP_000237 NP_001273331 NP_001273332 NP_001366259 NP_001366260 NP_001366261 NP_001366262 NP_001366263 NP_001230689 NP_001230690 NP_001289547 NP_001289548 NP_031601 Location (UCSC) Chr 16: 10.87 – 10.94 Mb Chr 16: 10.3 – 10.35 Mb PubMed search [3] [4]
Wikidata
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Function

CIITA mRNA can only be detected in human leukocyte antigen (HLA) system class II-positive cell lines and tissues. This highly restricted tissue distribution suggests that expression of HLA class II genes is to a large extent under the control of CIITA.^[7] However, CIITA does not appear to directly bind to DNA.^[7] Instead CIITA functions through activation of the transcription factor RFX5.^[8] Hence CIITA is classified as a transcriptional coactivator.

The CIITA protein contains an acidic transcriptional activation domain, 4 LRRs (leucine-rich repeats) and a GTP binding domain.^[9] The protein uses GTP binding to facilitate its own transport into the nucleus.^[10] Once in the nucleus, the protein acts as a positive regulator of class II major histocompatibility complex gene transcription, and is often referred to as the "master control factor" for the expression of these genes.^[11][12]

CIITA expression is induced by interferon gamma, possibly assisted by other signals.^[13] MHC II expression in intestinal epithelial cells is upregulated under inflammation.^[13]

Interactions

CIITA has been shown to interact with:

• MAPK1,^[14]
• Nuclear receptor coactivator 1,^[15]
• RFX5,^[8][16]
• RFXANK,^[16][17]
• XPO1,^[14][18] and
• ZXDC.^[19][20]

See also

• MHC class II