The nuclear localization pattern and interaction partners of GTF2IRD1 demonstrate a role in chromatin regulation.
GTF2IRD1 is one of the three members of the GTF2I gene family, clustered on chromosome 7 within a 1.8 Mb region that is prone to duplications and deletions in humans. Hemizygous deletions cause Williams-Beuren syndrome (WBS) and duplications cause WBS duplication syndrome. These copy number variations disturb a variety of developmental systems and neurological functions. Human mapping data and analyses of knockout mice show that GTF2IRD1 and GTF2I underpin the craniofacial abnormalities, mental retardation, visuospatial deficits and hypersociability of WBS. However, the cellular role of the GTF2IRD1 protein is poorly understood due to its very low abundance and a paucity of reagents. Here, for the first time, we show that endogenous GTF2IRD1 has a punctate pattern in the nuclei of cultured human cell lines and neurons. To probe the functional relationships of GTF2IRD1 in an unbiased manner, yeast two-hybrid libraries were screened, isolating 38 novel interaction partners, which were validated in mammalian cell lines. These relationships illustrate GTF2IRD1 function, as the isolated partners are mostly involved in chromatin modification and transcriptional regulation, whilst others indicate an unexpected role in connection with the primary cilium. Mapping of the sites of protein interaction also indicates key features regarding the evolution of the GTF2IRD1 protein. These data provide a visual and molecular basis for GTF2IRD1 nuclear function that will lead to an understanding of its role in brain, behaviour and human disease.
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia.
Paulina
P
Carmona-Mora
Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.
Jocelyn
J
Widagdo
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia.
Florence
F
Tomasetig
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia.
Cesar P
CP
Canales
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia.
Yeojoon
Y
Cha
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia.
Wei
W
Lee
Centre for Neural Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia.
Abdullah
A
Alshawaf
Centre for Neural Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia.
Mirella
M
Dottori
Biomedical Imaging Facility, Mark Wainwright Analytical Centre, UNSW Australia, Sydney, NSW, 2052, Australia.
Renee M
RM
Whan
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia.
Edna C
EC
Hardeman
Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia. s.palmer@unsw.edu.au.
Stephen J
SJ
Palmer
D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D002923:Cilia / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D002843:Chromatin; D004268:DNA-Binding Proteins; C405493:GTF2IRD1 protein, human; D009124:Muscle Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators