title: Characterization of nuclear foci-targeting of Luman/CREB3 recruitment factor (LRF/CREBRF) and its potential role in inhibition of herpes simplex virus-1 replication.
abstract: The recently identified Luman/CREB3-binding partner LRF (Luman/CREB3 recruitment factor) was shown to localize to discrete sub-nuclear foci. Luman is implicated in herpes simplex virus-1 (HSV-1) latency/reactivation and the unfolded protein response (UPR) pathway; therefore, we sought to characterize the formation of the LRF nuclear foci in the context of cellular signaling and HSV-1 replication. Here, we mapped the nuclear foci-targeting sequence to the central region containing the first leucine zipper (a.a.415-519), and found that the integrity of the whole region appears essential for LRF foci formation. LRF foci integrity was unaffected by inhibition of cellular DNA replication and translation, however, disruption of transcription resulted in altered LRF localization. When compared to other cellular and viral foci LRF co-localized with the nuclear receptor co-activator GRIP1, while the HSV-1 gene products ICP4, ICP27 and VP13/14 disrupted foci formation to varying degrees. Interestingly, cells over-expressing LRF were resistant to productive HSV-1 infection and this resistance was dependent upon protein targeting and an N-terminal transactivation domain. When LRF knockdown cells were subjected to primary infection, HSV-1 gene expression and progeny virus yield were enhanced by ∼3 fold compared to wildtype cells. Taken together, these results indicate that LRF is a key regulator that may act direct or indirectly as a repressor of essential genes required for productive viral infection.
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada; Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, B.C., V5A 1S6, Canada.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Audas
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Philip W
authors.initials: PW
authors.lastname: Hardy-Smith
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Jenna
authors.initials: J
authors.lastname: Penney
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Tiegh
authors.initials: T
authors.lastname: Taylor
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada. Electronic address: rlu@uoguelph.ca.
authors.forename: Ray
authors.initials: R
authors.lastname: Lu
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D018259:Herpesvirus 1, Human / Q000502:physiology*; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D014157:Transcription Factors / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D056811:Unfolded Protein Response; D014709:Vero Cells; D014779:Virus Replication / Q000502:physiology*
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins
keywords: CREB3/Luman; CREBRF/LRF; Herpes simplex virus; Nuclear foci; Unfolded protein response