Characterization of hampin/MSL1 as a node in the nuclear interactome

Abstract

Hampin, homolog of drosophila MSL1, is a partner of histone acetyltransferase MYST1/MOF. Functions of these proteins remain poorly understood beyond their participation in chromatin remodeling complex MSL. In order to identify new proteins interacting with hampin, we screened a mouse cDNA library in yeast two-hybrid system with mouse hampin as bait and found five highconfidence interactors: MYST1, TPR proteins TTC4 and KIAA0103, NOP17 (homolog of a yeast nucleolar protein) and transcription factor GC BP. Subsequently, all these proteins were used as baits in library screenings and more new interactions were found: tumor suppressor RASSF1C and spliceosome component PRP3 for KIAA0103, ring finger RNF10 for RASSF1C, and RNA polymerase II regulator NELF-C for MYST1. The majority of the observed interactions was confirmed in vitro by pull-down of bacterially expressed proteins. Reconstruction of a fragment of mammalian interactome suggests that hampin may be linked to diverse regulatory processes in the nucleus.

The Hsp90 Cochaperones Cpr6, Cpr7, and Cns1 Interact with the Intact Ribosome

“…Human and Drosophila homologs (TTC4 and Dpit47, respectively), interact with Hsp90, as well as DNA polymerase alpha, the replication protein Cdc6, the histone acetyltransferase MYST/MOF, and the transcriptional initiation factor TFIIIB (48)(49)(50)(51)(52). No specific clients of yeast Cns1 have been previously identified.…”

Nuclear transport of protein TTC4 depends on the cell cycle

“…Antibodies Rabbit anti-TTC4 antibodies were as previously described (Dmitriev et al 2007). The anti-5′-bromo-2-deoxyuridine (BrdU) monoclonal antibody (BU33) was purchased from Sigma-Aldrich (St Louis, Mo., USA).…”

“…Hampin B-GFP chimera was obtained by cloning PCR-amplified mouse hampin B ORF into pEGFP-N3 vector (Clontech), Plasmid DNA "hampin C-GFP" was as described earlier (Dmitriev et al 2006 Immunocytochemistry and Western blotting The procedures for immunofluorescence microscopy were performed as described earlier (Dmitriev et al 2007). Briefly, cells grown on coverslips were fixed in methanol (−20°C, 40 min) or in 4% formaldehyde in phosphate-buffered saline (20°C, 10 min).…”

“…Oligonucleotide primers specific for TTC4 and D-glyceraldehyde-3-phosphate dehydrogenase cDNA were as described earlier (Dmitriev et al 2005(Dmitriev et al , 2007.…”

“…Moreover, TTC4 and Dpit47 interact with another protein involved in DNA replication, viz., CDC6, and this property is conserved from Drosophila to humans (Crevel et al 2008). TTC4 protein interactions might be much more complex, because TTC4 also interacts with hampin/MSL1, a component of the MYST1 histone acetyltransferase complex, which in turn has at least five components (Dmitriev et al 2007). Both MYST1 and CDC6 proteins are involved in tumorigenesis: CDC6 has proto-oncogenic activity (Borlado and Méndez 2008), and the downregulation of MYST1 is characteristic for medulloblastomas (Pfister et al 2008).…”