The chicken ovalbumin upstream promoter transcription factor (COUP-TFs) proteins are members of the nuclear receptor family of intracellular transcription factors.[1]  There are two variants of the COUP-TFs, labeled as COUP-TFI and COUP-TFII encoded by the NR2F1 and NR2F2 genes respectively. 
COUP-TFs play critical roles in the development of organisms.[2] 
 References
   - ^ Qiu Y, Krishnan V, Zeng Z, Gilbert DJ, Copeland NG, Gibson L, Yang-Feng T, Jenkins NA, Tsai MJ, Tsai SY (1995). "Isolation, characterization, and chromosomal localization of mouse and human COUP-TF I and II genes". Genomics. 29 (1): 240–6. doi:10.1006/geno.1995.1237. PMID 8530078. 
- ^ Park JI, Tsai SY, Tsai MJ (2003). "Molecular mechanism of chicken ovalbumin upstream promoter-transcription factor (COUP-TF) actions" (PDF). The Keio Journal of Medicine. 52 (3): 174–81. doi:10.2302/kjm.52.174. PMID 14529150. 
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| | (1) Basic domains | 
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 | | (1.1) Basic leucine zipper (bZIP) |  | 
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 | (1.2) Basic helix-loop-helix (bHLH) | | Group A |  | 
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 | Group B |  | 
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 | Group C bHLH-PAS
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 | Group D |  | 
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 | Group E |  | 
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 | Group F bHLH-COE
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 | (1.3) bHLH-ZIP |  | 
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 | (1.4) NF-1 |  | 
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 | (1.5) RF-X |  | 
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 | (1.6) Basic helix-span-helix (bHSH) |  | 
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| | (2) Zinc finger DNA-binding domains | 
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 | | (2.1) Nuclear receptor (Cys4) | | subfamily 1 |  | 
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 | subfamily 2 |  | 
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 | subfamily 3 |  | 
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 | subfamily 4 |  | 
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 | subfamily 5 |  | 
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 | subfamily 6 |  | 
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 | subfamily 0 |  | 
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 | (2.2) Other Cys4 |  | 
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 | (2.3) Cys2His2 |  | 
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 | (2.4) Cys6 |  | 
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 | (2.5) Alternating composition |  | 
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 | (2.6) WRKY |  | 
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| | (4) β-Scaffold factors with minor groove contacts | 
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| |  (0) Other transcription factors | 
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| see also transcription factor/coregulator deficiencies |