The Gammaretroviral p12 protein has multiple domains that function during the early stages of replication

Wight, Darren J.; Boucherit, Virginie; Nader, Mirella; Allen, David J.; Taylor, Ian A.; Bishop, Kate N.

doi:10.1186/1742-4690-9-83

Cited by 28 publications

(81 citation statements)

References 37 publications

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Section: Discussionsupporting

confidence: 66%

“…Recent findings indicate that the N terminus of p12 plays a role in capsid core disassembly (12). Our results correlate the function of the p12 C terminus to mitotic chromatin tethering (12,25). Live-cell imaging indicates p12-labeled PICs traffic and tether to the mitotic chromatin after nuclear envelope breakdown, and the p12-PM14 mutation ablates tethering (25).…”

Section: Discussionsupporting

confidence: 58%

“…From this work it was proposed that p12 might have a role in nuclear retention (11). Further investigation demonstrated that mutations in the N terminus of p12 affect very early events in the virus life cycle, possibly through stabilization of the viral core, whereas mutations in the C terminus of p12 may affect chromatin binding (12). Using tagged p12, complexes were detected by immunofluorescence in the cytoplasm early after viral infection, and these complexes traffic toward the nucleus and later accumulate adjacent to mitotic chromosomes, supporting a role of p12 in chromatin binding (8).…”

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confidence: 99%

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Viral DNA tethering domains complement replication-defective mutations in the p12 protein of MuLV Gag

Schneider¹,

Brzezinski²,

Aiyer³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The p12 protein of murine leukemia virus (MuLV) group-specific antigen (Gag) is associated with the preintegration complex, and mutants of p12 (PM14) show defects in nuclear entry or retention. Here we show that p12 proteins engineered to encode peptide sequences derived from known viral tethering proteins can direct chromatin binding during the early phase of viral replication and rescue a lethal p12-PM14 mutant. Peptides studied included segments of Kaposi sarcoma herpesvirus latency-associated nuclear antigen (LANA) 1-23 , human papillomavirus 8 E2, and prototype foamy virus chromatin-binding sequences. Amino acid substitutions in Kaposi sarcoma herpesvirus LANA and prototype foamy virus chromatin-binding sequences that blocked nucleosome association failed to rescue MuLV p12-PM14. Rescue by a larger LANA peptide, LANA 1-32 , required second-site mutations that are predicted to reduce peptide binding affinity to chromosomes, suggesting that excessively high binding affinity interfered with Gag/p12 function. This is supported by confocal microscopy of chimeric p12-GFP fusion constructs showing the reverted proteins had weaker association to condensed mitotic chromosomes. Analysis of the integration-site selection of these chimeric viruses showed no significant change in integration profile compared with wild-type MuLV, suggesting release of the tethered p12 post mitosis, before viral integration. gammaretroviral vectors | retroviral integration | nuclear retention

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Section: Discussionsupporting

confidence: 66%

Section: Discussionsupporting

confidence: 58%

mentioning

confidence: 99%

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Viral DNA tethering domains complement replication-defective mutations in the p12 protein of MuLV Gag

Schneider¹,

Brzezinski²,

Aiyer³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…In striking similarity to PFV GAG, MLV P12 associates with mitotic chromosomes, and this property depends on an Argrich motif within its C-terminal region (39). Although deletions of or substitutions within this putative nucleosome-binding region abolish MLV infectivity, its replacement with heterologous chromatin-binding peptides, such as the PFV GAG CBS, are tolerated (39,40). Thus the loss of chromatin-tethering function via a gag product seems to be even more catastrophic for MLV than for the spumaviruses, which retain the ability to complete integration upon CBS abrogation (Fig.…”

Section: Discussionmentioning

confidence: 99%

Structural basis for spumavirus GAG tethering to chromatin

Lesbats

Serrao

Maskell

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The interactions between a retrovirus and host cell chromatin that underlie integration and provirus expression are poorly understood. The prototype foamy virus (PFV) structural protein GAG associates with chromosomes via a chromatin-binding sequence (CBS) located within its C-terminal region. Here, we show that the PFV CBS is essential and sufficient for a direct interaction with nucleosomes and present a crystal structure of the CBS bound to a mononucleosome. The CBS interacts with the histone octamer, engaging the H2A-H2B acidic patch in a manner similar to other acidic patch-binding proteins such as herpesvirus latency-associated nuclear antigen (LANA). Substitutions of the invariant arginine anchor residue in GAG result in global redistribution of PFV and macaque simian foamy virus (SFV mac ) integration sites toward centromeres, dampening the resulting proviral expression without affecting the overall efficiency of integration. Our findings underscore the importance of retroviral structural proteins for integration site selection and the avoidance of genomic junkyards.retrovirus | integration | nucleosome | chromatin-binding

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“…MLV requires cells to undergo mitosis to gain nuclear entry and requires a mechanism to remain nuclear after mitosis is complete, since integration occurs after exit from mitosis (1,2). p12 accomplishes this by binding the viral preintegration complex (PIC) with its N terminus (3) and nuclear chromatin with its C terminus (2)(3)(4). This p12 chromatin binding motif was shown to not affect MLV integration targeting to transcriptional start sites (4), and integrase (IN) binding to BET proteins was found to achieve the integration targeting (5)(6)(7)(8).…”

mentioning

confidence: 99%

Repression of the Chromatin-Tethering Domain of Murine Leukemia Virus p12

Brzezinski

Modi

Liu

et al. 2016

J Virol

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Murine leukemia virus (MLV) p12, encoded within Gag, binds the viral preintegration complex (PIC) to the mitotic chromatin. This acts to anchor the viral PIC in the nucleus as the nuclear envelope re-forms postmitosis. Mutations within the p12 C terminus (p12 PM13 to PM15) block early stages in viral replication. Within the p12 PM13 region (p12 60 PSPMA 65 ), our studies indicated that chromatin tethering was not detected when the wild-type (WT) p12 protein (M63) was expressed as a green fluorescent protein (GFP) fusion; however, constructs bearing p12-I63 were tethered. N-terminal truncations of the activated p12-I63-GFP indicated that tethering increased further upon deletion of p12 25 DLLTEDPPPY 34 , which includes the late domain required for viral assembly. The p12 PM15 sequence (p12 70 RREPP 74 ) is critical for wild-type viral viability; however, virions bearing the PM15 mutation (p12 70 AAAAA 74 ) with a second M63I mutant were viable, with a titer 18-fold lower than that of the WT. The p12 M63I mutation amplified chromatin tethering and compensated for the loss of chromatin binding of p12 PM15. Rescue of the p12-M63-PM15 nonviable mutant with prototype foamy virus (PFV) and Kaposi's sarcoma herpesvirus (KSHV) tethering sequences confirmed the function of p12 70 -74 in chromatin binding. Minimally, full-strength tethering was seen with only p12 61 SPIASRLRGRR 71 fused to GFP. These results indicate that the p12 C terminus alone is sufficient for chromatin binding and that the presence of the p12 25 DLLTEDPPPY 34 motif in the N terminus suppresses the ability to tether. IMPORTANCEThis study defines a regulatory mechanism controlling the differential roles of the MLV p12 protein in early and late replication. During viral assembly and egress, the late domain within the p12 N terminus functions to bind host vesicle release factors. During viral entry, the C terminus of p12 is required for tethering to host mitotic chromosomes. Our studies indicate that the p12 domain including the PPPY late sequence temporally represses the p12 chromatin tethering motif. Maximal p12 tethering was identified with only an 11-amino-acid minimal chromatin tethering motif encoded at p12 61-71 . Within this region, the p12-M63I substitution switches p12 into a tethering-competent state, partially rescuing the p12-PM15 tethering mutant. A model for how this conformational change regulates early versus late functions is presented.T he p12 structural protein of murine leukemia virus (MLV) was recently identified as a critical chromatin tether for the early viral life cycle. MLV requires cells to undergo mitosis to gain nuclear entry and requires a mechanism to remain nuclear after mitosis is complete, since integration occurs after exit from mitosis (1, 2). p12 accomplishes this by binding the viral preintegration complex (PIC) with its N terminus (3) and nuclear chromatin with its C terminus (2-4). This p12 chromatin binding motif was shown to not affect MLV integration targeting to transcriptional start sites (4), and inte...

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The Gammaretroviral p12 protein has multiple domains that function during the early stages of replication

Cited by 28 publications

References 37 publications

Viral DNA tethering domains complement replication-defective mutations in the p12 protein of MuLV Gag

Viral DNA tethering domains complement replication-defective mutations in the p12 protein of MuLV Gag

Structural basis for spumavirus GAG tethering to chromatin

Repression of the Chromatin-Tethering Domain of Murine Leukemia Virus p12

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