Human Homolog of Drosophila Ariadne (HHARI) is a marker of cellular proliferation associated with nuclear bodies.
HHARI (also known as ARIH1) is an ubiquitin-protein ligase and is the cognate of the E2, UbcH7 (UBE2L3). To establish a functional role for HHARI in cellular proliferation processes, we performed a reverse genetics screen that identified n=86/522 (16.5%) ubiquitin conjugation components that have a statistically significant effect on cell proliferation, which included HHARI as a strong hit. We then produced and validated a panel of specific antibodies that establish HHARI as both a nuclear and cytoplasmic protein that is expressed in all cell types studied. HHARI was expressed at higher levels in nuclei, and co-localized with nuclear bodies including Cajal bodies (p80 coilin, NOPP140), PML and SC35 bodies. We confirmed reduced cellular proliferation after ARIH1 knockdown with individual siRNA duplexes, in addition to significantly increased levels of apoptosis, an increased proportion of cells in G2 phase of the cell cycle, and significant reductions in total cellular RNA levels. In head and neck squamous cell carcinoma biopsies, there are higher levels of HHARI expression associated with increased levels of proliferation, compared to healthy control tissues. We demonstrate that HHARI is associated with cellular proliferation, which may be mediated through its interaction with UbcH7 and modification of proteins in nuclear bodies.
Division of Clinical Sciences, Leeds Institute of Molecular Medicine, Wellcome Trust Brenner Building, University of Leeds, Leeds, West Yorkshire, UK.
Fatima
F
Elmehdawi
Gabrielle
G
Wheway
Katarzyna
K
Szymanska
Matthew
M
Adams
Alec S
AS
High
Colin A
CA
Johnson
Philip A
PA
Robinson
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D049109:Cell Proliferation; D002478:Cells, Cultured; D020541:Coiled Bodies / Q000378:metabolism* / Q000502:physiology; D004330:Drosophila / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D011485:Protein Binding; D017385:Sequence Homology; D044767:Ubiquitin-Protein Ligases
C412166:Ari-1 protein, Drosophila; D015415:Biomarkers; D002352:Carrier Proteins; D029721:Drosophila Proteins; C419193:ARIH1 protein, human; D044767:Ubiquitin-Protein Ligases