Missense mutations that cause Van der Woude syndrome and popliteal pterygium syndrome affect the DNA-binding and transcriptional activation functions of IRF6.
Cleft lip and cleft palate (CLP) are common disorders that occur either as part of a syndrome, where structures other than the lip and palate are affected, or in the absence of other anomalies. Van der Woude syndrome (VWS) and popliteal pterygium syndrome (PPS) are autosomal dominant disorders characterized by combinations of cleft lip, CLP, lip pits, skin-folds, syndactyly and oral adhesions which arise as the result of mutations in interferon regulatory factor 6 (IRF6). IRF6 belongs to a family of transcription factors that share a highly conserved N-terminal, DNA-binding domain and a less well-conserved protein-binding domain. To date, mutation analyses have suggested a broad genotype-phenotype correlation in which missense and nonsense mutations occurring throughout IRF6 may cause VWS; in contrast, PPS-causing mutations are highly associated with the DNA-binding domain, and appear to preferentially affect residues that are predicted to interact directly with the DNA. Nevertheless, this genotype-phenotype correlation is based on the analysis of structural models rather than on the investigation of the DNA-binding properties of IRF6. Moreover, the effects of mutations in the protein interaction domain have not been analysed. In the current investigation, we have determined the sequence to which IRF6 binds and used this sequence to analyse the effect of VWS- and PPS-associated mutations in the DNA-binding domain of IRF6. In addition, we have demonstrated that IRF6 functions as a co-operative transcriptional activator and that mutations in the protein interaction domain of IRF6 disrupt this activity.
Little
Hayley J
HJ
Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
Rorick
Nicholas K
NK
Su
Ling-I
LI
Baldock
Clair
C
Malhotra
Saimon
S
Jowitt
Tom
T
Gakhar
Lokesh
L
Subramanian
Ramaswamy
R
Schutte
Brian C
BC
Dixon
Michael J
MJ
Shore
Paul
P
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D002971:Cleft Lip / Q000235:genetics* / Q000378:metabolism; D002972:Cleft Palate / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D050835:Interferon Regulatory Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C109803:IRF6 protein, human; D050835:Interferon Regulatory Factors