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Protein

Transcription factor E2f1

Gene

E2f1

Organism
Drosophila melanogaster (Fruit fly)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Transcriptional activator that binds to E2f sites. Required for wild-type growth in mitotic and polytene tissues, Contributes to the expression of replication genes at the G1-S transition and Cyclin E. Activates cell proliferation in wing imaginal disk, which requires expression of vg.3 Publications

Regions

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
DNA bindingi253 – 31866Sequence analysisAdd
BLAST

GO - Molecular functioni

  • DNA binding Source: FlyBase
  • RNA polymerase II regulatory region DNA binding Source: FlyBase
  • transcriptional activator activity, RNA polymerase II core promoter proximal region sequence-specific binding Source: FlyBase
  • transcription factor activity, sequence-specific DNA binding Source: FlyBase
  • transcription factor binding Source: FlyBase

GO - Biological processi

  • antimicrobial humoral response Source: FlyBase
  • dendrite morphogenesis Source: FlyBase
  • DNA endoreduplication Source: FlyBase
  • eggshell chorion gene amplification Source: FlyBase
  • G1/S transition of mitotic cell cycle Source: FlyBase
  • growth Source: FlyBase
  • imaginal disc-derived wing morphogenesis Source: FlyBase
  • imaginal disc development Source: FlyBase
  • larval lymph gland hemopoiesis Source: FlyBase
  • muscle tissue development Source: FlyBase
  • negative regulation of transcription from RNA polymerase II promoter Source: FlyBase
  • neuron development Source: FlyBase
  • nurse cell apoptotic process Source: FlyBase
  • positive regulation of cell proliferation Source: FlyBase
  • positive regulation of gene expression Source: FlyBase
  • positive regulation of nurse cell apoptotic process Source: FlyBase
  • positive regulation of transcription, DNA-templated Source: FlyBase
  • positive regulation of transcription from RNA polymerase II promoter Source: FlyBase
  • regulation of cell cycle Source: FlyBase
  • regulation of execution phase of apoptosis Source: FlyBase
  • regulation of glucose metabolic process Source: FlyBase
  • regulation of hemocyte proliferation Source: FlyBase
  • regulation of transcription involved in G1/S transition of mitotic cell cycle Source: FlyBase
  • ventral cord development Source: FlyBase
Complete GO annotation...

Keywords - Molecular functioni

Activator, Developmental protein

Keywords - Biological processi

Transcription, Transcription regulation

Keywords - Ligandi

DNA-binding

Enzyme and pathway databases

ReactomeiR-DME-113501. Inhibition of replication initiation of damaged DNA by RB1/E2F1.
R-DME-113510. E2F mediated regulation of DNA replication.
R-DME-1538133. G0 and Early G1.
R-DME-68689. CDC6 association with the ORC:origin complex.
R-DME-68911. G2 Phase.
R-DME-69205. G1/S-Specific Transcription.
R-DME-69298. Association of licensing factors with the pre-replicative complex.

Names & Taxonomyi

Protein namesi
Recommended name:
Transcription factor E2f1
Alternative name(s):
dE2F
Gene namesi
Name:E2f1Imported
Synonyms:E2fImported
ORF Names:CG6376Imported
OrganismiDrosophila melanogaster (Fruit fly)
Taxonomic identifieri7227 [NCBI]
Taxonomic lineageiEukaryotaMetazoaEcdysozoaArthropodaHexapodaInsectaPterygotaNeopteraEndopterygotaDipteraBrachyceraMuscomorphaEphydroideaDrosophilidaeDrosophilaSophophora
Proteomesi
  • UP000000803 Componenti: Chromosome 3R

Organism-specific databases

FlyBaseiFBgn0011766. E2f1.

Subcellular locationi

GO - Cellular componenti

  • nucleoplasm Source: Reactome
  • nucleus Source: FlyBase
  • Rb-E2F complex Source: FlyBase
Complete GO annotation...

Keywords - Cellular componenti

Nucleus

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi153 – 1564ITNY → ATAA: Abolishes interaction with PCNA and subsequent degradation by the proteasome.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 805805Transcription factor E2f1PRO_0000219474Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei434 – 4341Phosphoserine1 Publication

Post-translational modificationi

Ubiquitinated by the DCX(DTL) complex, also named CRL4(CDT2) complex, leading to its degradation during S phase. Ubiquitination by the DCX(DTL) complex is essential for cell cycle control and is PCNA-dependent: interacts with PCNA via its PIP-box, while the presence of the containing the 'K+4' motif in the PIP box, recruit the DCX(DTL) complex, leading to its degradation.1 Publication

Keywords - PTMi

Phosphoprotein, Ubl conjugation

Proteomic databases

PaxDbiQ27368.
PRIDEiQ27368.

PTM databases

iPTMnetiQ27368.

Expressioni

Tissue specificityi

Segmentally repeated expression throughout early embryos is restricted to the ventral nerve cord in later embryos.1 Publication

Developmental stagei

Throughout embryonic development.1 Publication

Gene expression databases

BgeeiQ27368.
ExpressionAtlasiQ27368. differential.
GenevisibleiQ27368. DM.

Interactioni

Subunit structurei

Heterodimer of E2f and Dp. Cooperates to give sequence-specific DNA binding and optimal trans-activation. Interacts with PCNA.1 Publication

Binary interactionsi

WithEntry#Exp.IntActNotes
RbfQ244722EBI-108384,EBI-145741

GO - Molecular functioni

  • transcription factor binding Source: FlyBase

Protein-protein interaction databases

BioGridi67516. 27 interactions.
DIPiDIP-21076N.
IntActiQ27368. 4 interactions.
MINTiMINT-1019344.
STRINGi7227.FBpp0083516.

Structurei

3D structure databases

ProteinModelPortaliQ27368.
SMRiQ27368. Positions 253-318.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni318 – 41194DimerizationSequence analysisAdd
BLAST

Motif

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Motifi147 – 16115PIP-box K+4 motifAdd
BLAST

Compositional bias

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Compositional biasi14 – 196Poly-Ser
Compositional biasi64 – 685Poly-Asn
Compositional biasi115 – 12511Poly-AlaAdd
BLAST
Compositional biasi129 – 14315Gly-richAdd
BLAST
Compositional biasi245 – 2495Poly-Ser
Compositional biasi519 – 57355Gly-richAdd
BLAST
Compositional biasi525 – 5339Poly-Gln
Compositional biasi594 – 6018Poly-Ala
Compositional biasi701 – 71010Poly-Gly

Domaini

The PIP-box K+4 motif mediates both the interaction with PCNA and the recruitment of the DCX(DTL) complex: while the PIP-box interacts with PCNA, the presence of the K+4 submotif, recruits the DCX(DTL) complex, leading to its ubiquitination.1 Publication

Sequence similaritiesi

Belongs to the E2F/DP family.Curated

Phylogenomic databases

eggNOGiKOG2577. Eukaryota.
ENOG410XNYI. LUCA.
GeneTreeiENSGT00550000074403.
InParanoidiQ27368.
KOiK06620.
OMAiPLFNNID.
OrthoDBiEOG7VQJCV.
PhylomeDBiQ27368.

Family and domain databases

Gene3Di1.10.10.10. 1 hit.
InterProiIPR015633. E2F.
IPR032198. E2F_CC-MB.
IPR003316. E2F_WHTH_DNA-bd_dom.
IPR011991. WHTH_DNA-bd_dom.
[Graphical view]
PANTHERiPTHR12081. PTHR12081. 3 hits.
PfamiPF16421. E2F_CC-MB. 1 hit.
PF02319. E2F_TDP. 1 hit.
[Graphical view]
SMARTiSM01372. E2F_TDP. 1 hit.
[Graphical view]
SUPFAMiSSF46785. SSF46785. 1 hit.

Sequencei

Sequence statusi: Complete.

Q27368-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MSKFFVNVAP INNSNSSSSH TTTSSNTQRH QQHQQHYGGS GTTGHTMVAR
60 70 80 90 100
RLNYDLHGGT TSINNNNNIV IKNESVDLDY DHVLSSSDSN SNGGVAAHLR
110 120 130 140 150
DHVYISLDKG HNTGAVATAA AAATAGHTQQ QLQQQHHHQN QQQRKATGKS
160 170 180 190 200
NDITNYYKVK RRPHAVSDEI HPKKQAKQSA HHQTVYQKHT ASSAPQQLRH
210 220 230 240 250
SHHQLRHDAD AELDEDVVER VAKPASHHPF SLSTPQQQLA ASVASSSSSG
260 270 280 290 300
DRNRADTSLG ILTKKFVDLL QESPDGVVDL NEASNRLHVQ KRRIYDITNV
310 320 330 340 350
LEGINILEKK SKNNIQWRCG QSMVSQERSR HIEADSLRLE QQENELNKAI
360 370 380 390 400
DLMRENLAEI SQEVENSGGM AYVTQNDLLN VDLFKDQIVI VIKAPPEAKL
410 420 430 440 450
VLPNTKLPRE IYVKAENSGE INVFLCHDTS PENSPIAPGA GYVGAPGAGC
460 470 480 490 500
VRTATSTRLH PLTNQRLNDP LFNNIDAMST KGLFQTPYRS ARNLSKSIEE
510 520 530 540 550
AAKQSQPEYN NICDIAMGQH HNLNQQQQQQ QQQLLQQPEE DDVDVELNQL
560 570 580 590 600
VPTLTNPVVR THQFQQHQQP SIQELFSSLT ESSPPTPTKR RREAAAAAIA
610 620 630 640 650
AGSSTTATTT LNSHNNRNHS NHSNHSNHSS SNNSKSQPPT IGYGSSQRRS
660 670 680 690 700
DVPMYNCAME GATTTSATAD TTAATSRSAA ASSLQMQFAA VAESNNGSSS
710 720 730 740 750
GGGGGGGGYG SIAGAGANAD PHQPYSHDRN SLPPGVADCD ANSNSSSVTL
760 770 780 790 800
QGLDALFNDI GSDYFSNDIA FVSINPPDDN DYPYALNANE GIDRLFDFGS

DAYGP
Length:805
Mass (Da):87,460
Last modified:June 1, 2001 - v2
Checksum:iBD49C813DDB2A77D
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti127 – 1271H → Q in CAA55186 (PubMed:8114698).Curated
Sequence conflicti127 – 1271H → Q in AAA19003 (PubMed:8022787).Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U10184 mRNA. Translation: AAA19003.1.
X78421 mRNA. Translation: CAA55186.1.
AB011813 Genomic DNA. Translation: BAA32746.1.
AE014297 Genomic DNA. Translation: AAF55904.1.
AE014297 Genomic DNA. Translation: AAN13878.1.
AE014297 Genomic DNA. Translation: AAN13879.1.
BT016096 mRNA. Translation: AAV36981.1.
PIRiA56199.
RefSeqiNP_001287455.1. NM_001300526.1.
NP_524437.2. NM_079713.3.
NP_732646.1. NM_169961.3.
NP_732647.1. NM_169962.3.
UniGeneiDm.7299.

Genome annotation databases

EnsemblMetazoaiFBtr0084117; FBpp0083516; FBgn0011766.
FBtr0084118; FBpp0083517; FBgn0011766.
FBtr0084119; FBpp0083518; FBgn0011766.
FBtr0346157; FBpp0311985; FBgn0011766.
GeneIDi42550.
KEGGidme:Dmel_CG6376.
UCSCiCG6376-RB. d. melanogaster.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U10184 mRNA. Translation: AAA19003.1.
X78421 mRNA. Translation: CAA55186.1.
AB011813 Genomic DNA. Translation: BAA32746.1.
AE014297 Genomic DNA. Translation: AAF55904.1.
AE014297 Genomic DNA. Translation: AAN13878.1.
AE014297 Genomic DNA. Translation: AAN13879.1.
BT016096 mRNA. Translation: AAV36981.1.
PIRiA56199.
RefSeqiNP_001287455.1. NM_001300526.1.
NP_524437.2. NM_079713.3.
NP_732646.1. NM_169961.3.
NP_732647.1. NM_169962.3.
UniGeneiDm.7299.

3D structure databases

ProteinModelPortaliQ27368.
SMRiQ27368. Positions 253-318.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi67516. 27 interactions.
DIPiDIP-21076N.
IntActiQ27368. 4 interactions.
MINTiMINT-1019344.
STRINGi7227.FBpp0083516.

PTM databases

iPTMnetiQ27368.

Proteomic databases

PaxDbiQ27368.
PRIDEiQ27368.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblMetazoaiFBtr0084117; FBpp0083516; FBgn0011766.
FBtr0084118; FBpp0083517; FBgn0011766.
FBtr0084119; FBpp0083518; FBgn0011766.
FBtr0346157; FBpp0311985; FBgn0011766.
GeneIDi42550.
KEGGidme:Dmel_CG6376.
UCSCiCG6376-RB. d. melanogaster.

Organism-specific databases

CTDi1869.
FlyBaseiFBgn0011766. E2f1.

Phylogenomic databases

eggNOGiKOG2577. Eukaryota.
ENOG410XNYI. LUCA.
GeneTreeiENSGT00550000074403.
InParanoidiQ27368.
KOiK06620.
OMAiPLFNNID.
OrthoDBiEOG7VQJCV.
PhylomeDBiQ27368.

Enzyme and pathway databases

ReactomeiR-DME-113501. Inhibition of replication initiation of damaged DNA by RB1/E2F1.
R-DME-113510. E2F mediated regulation of DNA replication.
R-DME-1538133. G0 and Early G1.
R-DME-68689. CDC6 association with the ORC:origin complex.
R-DME-68911. G2 Phase.
R-DME-69205. G1/S-Specific Transcription.
R-DME-69298. Association of licensing factors with the pre-replicative complex.

Miscellaneous databases

ChiTaRSiE2f2. fly.
GenomeRNAii42550.
PROiQ27368.

Gene expression databases

BgeeiQ27368.
ExpressionAtlasiQ27368. differential.
GenevisibleiQ27368. DM.

Family and domain databases

Gene3Di1.10.10.10. 1 hit.
InterProiIPR015633. E2F.
IPR032198. E2F_CC-MB.
IPR003316. E2F_WHTH_DNA-bd_dom.
IPR011991. WHTH_DNA-bd_dom.
[Graphical view]
PANTHERiPTHR12081. PTHR12081. 3 hits.
PfamiPF16421. E2F_CC-MB. 1 hit.
PF02319. E2F_TDP. 1 hit.
[Graphical view]
SMARTiSM01372. E2F_TDP. 1 hit.
[Graphical view]
SUPFAMiSSF46785. SSF46785. 1 hit.
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Functional properties of a Drosophila homolog of the E2F1 gene."
    Ohtani K., Nevins J.R.
    Mol. Cell. Biol. 14:1603-1612(1994) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA].
  2. "DNA-binding and trans-activation properties of Drosophila E2F and DP proteins."
    Dynlacht B.D., Brook A., Dembski M., Yenush L., Dyson N.
    Proc. Natl. Acad. Sci. U.S.A. 91:6359-6363(1994) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA].
    Tissue: Eye imaginal disk.
  3. "Specification of regions of DNA replication initiation during embryogenesis in the 65-kilobase DNApolalpha-dE2F locus of Drosophila melanogaster."
    Sasaki T., Sawado T., Yamaguchi M., Shinomiya T.
    Mol. Cell. Biol. 19:547-555(1999) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
    Strain: Oregon-R.
  4. "The genome sequence of Drosophila melanogaster."
    Adams M.D., Celniker S.E., Holt R.A., Evans C.A., Gocayne J.D., Amanatides P.G., Scherer S.E., Li P.W., Hoskins R.A., Galle R.F., George R.A., Lewis S.E., Richards S., Ashburner M., Henderson S.N., Sutton G.G., Wortman J.R., Yandell M.D.
    , Zhang Q., Chen L.X., Brandon R.C., Rogers Y.-H.C., Blazej R.G., Champe M., Pfeiffer B.D., Wan K.H., Doyle C., Baxter E.G., Helt G., Nelson C.R., Miklos G.L.G., Abril J.F., Agbayani A., An H.-J., Andrews-Pfannkoch C., Baldwin D., Ballew R.M., Basu A., Baxendale J., Bayraktaroglu L., Beasley E.M., Beeson K.Y., Benos P.V., Berman B.P., Bhandari D., Bolshakov S., Borkova D., Botchan M.R., Bouck J., Brokstein P., Brottier P., Burtis K.C., Busam D.A., Butler H., Cadieu E., Center A., Chandra I., Cherry J.M., Cawley S., Dahlke C., Davenport L.B., Davies P., de Pablos B., Delcher A., Deng Z., Mays A.D., Dew I., Dietz S.M., Dodson K., Doup L.E., Downes M., Dugan-Rocha S., Dunkov B.C., Dunn P., Durbin K.J., Evangelista C.C., Ferraz C., Ferriera S., Fleischmann W., Fosler C., Gabrielian A.E., Garg N.S., Gelbart W.M., Glasser K., Glodek A., Gong F., Gorrell J.H., Gu Z., Guan P., Harris M., Harris N.L., Harvey D.A., Heiman T.J., Hernandez J.R., Houck J., Hostin D., Houston K.A., Howland T.J., Wei M.-H., Ibegwam C., Jalali M., Kalush F., Karpen G.H., Ke Z., Kennison J.A., Ketchum K.A., Kimmel B.E., Kodira C.D., Kraft C.L., Kravitz S., Kulp D., Lai Z., Lasko P., Lei Y., Levitsky A.A., Li J.H., Li Z., Liang Y., Lin X., Liu X., Mattei B., McIntosh T.C., McLeod M.P., McPherson D., Merkulov G., Milshina N.V., Mobarry C., Morris J., Moshrefi A., Mount S.M., Moy M., Murphy B., Murphy L., Muzny D.M., Nelson D.L., Nelson D.R., Nelson K.A., Nixon K., Nusskern D.R., Pacleb J.M., Palazzolo M., Pittman G.S., Pan S., Pollard J., Puri V., Reese M.G., Reinert K., Remington K., Saunders R.D.C., Scheeler F., Shen H., Shue B.C., Siden-Kiamos I., Simpson M., Skupski M.P., Smith T.J., Spier E., Spradling A.C., Stapleton M., Strong R., Sun E., Svirskas R., Tector C., Turner R., Venter E., Wang A.H., Wang X., Wang Z.-Y., Wassarman D.A., Weinstock G.M., Weissenbach J., Williams S.M., Woodage T., Worley K.C., Wu D., Yang S., Yao Q.A., Ye J., Yeh R.-F., Zaveri J.S., Zhan M., Zhang G., Zhao Q., Zheng L., Zheng X.H., Zhong F.N., Zhong W., Zhou X., Zhu S.C., Zhu X., Smith H.O., Gibbs R.A., Myers E.W., Rubin G.M., Venter J.C.
    Science 287:2185-2195(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: Berkeley.
  5. Cited for: GENOME REANNOTATION.
    Strain: Berkeley.
  6. Stapleton M., Carlson J.W., Frise E., Kapadia B., Park S., Wan K.H., Yu C., Celniker S.E.
    Submitted (NOV-2006) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
    Strain: Berkeley.
    Tissue: Embryo.
  7. "Functional conservation of the cell cycle-regulating transcription factor DRTF1/E2F and its pathway of control in Drosophila melanogaster."
    Hao X.F., Alphey L., Bandara L.R., Lam E.W., Glover D., La Thangue N.B.
    J. Cell Sci. 108:2945-2954(1995) [PubMed] [Europe PMC] [Abstract]
    Cited for: TISSUE SPECIFICITY, DEVELOPMENTAL STAGE.
  8. "Mutations in Drosophila DP and E2F distinguish G1-S progression from an associated transcriptional program."
    Royzman I., Whittaker A.J., Orr-Weaver T.L.
    Genes Dev. 11:1999-2011(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  9. "Mutations of the Drosophila dDP, dE2F, and cyclin E genes reveal distinct roles for the E2F-DP transcription factor and cyclin E during the G1-S transition."
    Duronio R.J., Bonnette P.C., O'Farrell P.H.
    Mol. Cell. Biol. 18:141-151(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  10. "The Drosophila wing differentiation factor vestigial-scalloped is required for cell proliferation and cell survival at the dorso-ventral boundary of the wing imaginal disc."
    Delanoue R., Legent K., Godefroy N., Flagiello D., Dutriaux A., Vaudin P., Becker J.L., Silber J.
    Cell Death Differ. 11:110-122(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  11. "Intrinsic negative cell cycle regulation provided by PIP box- and Cul4Cdt2-mediated destruction of E2f1 during S phase."
    Shibutani S.T., de la Cruz A.F., Tran V., Turbyfill W.J. III, Reis T., Edgar B.A., Duronio R.J.
    Dev. Cell 15:890-900(2008) [PubMed] [Europe PMC] [Abstract]
    Cited for: UBIQUITINATION, DOMAIN PIP-BOX K+4 MOTIF, INTERACTION WITH PCNA, MUTAGENESIS OF 153-ILE--TYR-157.
  12. "Phosphoproteome analysis of Drosophila melanogaster embryos."
    Zhai B., Villen J., Beausoleil S.A., Mintseris J., Gygi S.P.
    J. Proteome Res. 7:1675-1682(2008) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT SER-434, IDENTIFICATION BY MASS SPECTROMETRY.
    Tissue: Embryo.

Entry informationi

Entry nameiE2F1_DROME
AccessioniPrimary (citable) accession number: Q27368
Secondary accession number(s): O77035, Q5U0Z6
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 1, 1997
Last sequence update: June 1, 2001
Last modified: July 6, 2016
This is version 142 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programDrosophila annotation project

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. Drosophila
    Drosophila: entries, gene names and cross-references to FlyBase
  2. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.