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The Murid Herpesvirus-4 gL regulates an entry-associated conformation change in gH.

Gillet L, Colaco S, Stevenson PG - PLoS ONE (2008)

Bottom Line: However, gH switched back to a gL-independent conformation after virion endocytosis.This switch coincided with a conformation switch in gB and with capsid release.Virions lacking gL constitutively expressed the down-stream form of gH, prematurely switched gB to its down-stream form, and showed premature capsid release with poor infectivity.

View Article: PubMed Central - PubMed

Affiliation: Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT
The glycoprotein H (gH)/gL heterodimer is crucial for herpesvirus membrane fusion. Yet how it functions is not well understood. The Murid Herpesvirus-4 gH, like that of other herpesviruses, adopts its normal virion conformation by associating with gL. However, gH switched back to a gL-independent conformation after virion endocytosis. This switch coincided with a conformation switch in gB and with capsid release. Virions lacking gL constitutively expressed the down-stream form of gH, prematurely switched gB to its down-stream form, and showed premature capsid release with poor infectivity. These data argue that gL plays a key role in regulating a gH and gB functional switch from cell binding to membrane fusion.

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Related in: MedlinePlus

gL-dependent gB conformational instability in MuHV-4-infected BHK-21 cells.BHK-21 cells were left uninfected (UI) or infected with gL− (gL−STOP, gL−DEL) or gL+ (wild-type, gL−DEL revertant) viruses (2 p.f.u./cell, 18 h). The cells were then trypsinized and stained with secondary antibody only (nil, solid lines) or for gN (mAb 3F7, dotted lines), gH-only (mAb MG-9B10, solid lines), gH/gL (mAb T2C12, dotted lines), the mAb BN-1A7+ virion gB conformation (gB vir, dotted lines) or the mAb MG-1A12+ pro-fusion gB conformation (gB fus, solid lines). The data are from 1 of 3 equivalent experiments.
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pone-0002811-g007: gL-dependent gB conformational instability in MuHV-4-infected BHK-21 cells.BHK-21 cells were left uninfected (UI) or infected with gL− (gL−STOP, gL−DEL) or gL+ (wild-type, gL−DEL revertant) viruses (2 p.f.u./cell, 18 h). The cells were then trypsinized and stained with secondary antibody only (nil, solid lines) or for gN (mAb 3F7, dotted lines), gH-only (mAb MG-9B10, solid lines), gH/gL (mAb T2C12, dotted lines), the mAb BN-1A7+ virion gB conformation (gB vir, dotted lines) or the mAb MG-1A12+ pro-fusion gB conformation (gB fus, solid lines). The data are from 1 of 3 equivalent experiments.

Mentions: Flow cytometry of infected BHK-21 cells provided further evidence of gB conformational instability in the absence of gL (Fig. 7). For an equivalent level of gN expression, BN-1A7 gB staining (pre-fusion) was weaker on cells infected with gL knockout viruses than with wild-type or revertant viruses, and MG-1A12 staining (post-fusion) was stronger. Thus, the premature capsid release of gL− virions reflected gH being in its down-stream gH-only form from the start, and gB engaging prematurely in membrane fusion after endocytosis.


The Murid Herpesvirus-4 gL regulates an entry-associated conformation change in gH.

Gillet L, Colaco S, Stevenson PG - PLoS ONE (2008)

gL-dependent gB conformational instability in MuHV-4-infected BHK-21 cells.BHK-21 cells were left uninfected (UI) or infected with gL− (gL−STOP, gL−DEL) or gL+ (wild-type, gL−DEL revertant) viruses (2 p.f.u./cell, 18 h). The cells were then trypsinized and stained with secondary antibody only (nil, solid lines) or for gN (mAb 3F7, dotted lines), gH-only (mAb MG-9B10, solid lines), gH/gL (mAb T2C12, dotted lines), the mAb BN-1A7+ virion gB conformation (gB vir, dotted lines) or the mAb MG-1A12+ pro-fusion gB conformation (gB fus, solid lines). The data are from 1 of 3 equivalent experiments.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2481400&req=5

pone-0002811-g007: gL-dependent gB conformational instability in MuHV-4-infected BHK-21 cells.BHK-21 cells were left uninfected (UI) or infected with gL− (gL−STOP, gL−DEL) or gL+ (wild-type, gL−DEL revertant) viruses (2 p.f.u./cell, 18 h). The cells were then trypsinized and stained with secondary antibody only (nil, solid lines) or for gN (mAb 3F7, dotted lines), gH-only (mAb MG-9B10, solid lines), gH/gL (mAb T2C12, dotted lines), the mAb BN-1A7+ virion gB conformation (gB vir, dotted lines) or the mAb MG-1A12+ pro-fusion gB conformation (gB fus, solid lines). The data are from 1 of 3 equivalent experiments.
Mentions: Flow cytometry of infected BHK-21 cells provided further evidence of gB conformational instability in the absence of gL (Fig. 7). For an equivalent level of gN expression, BN-1A7 gB staining (pre-fusion) was weaker on cells infected with gL knockout viruses than with wild-type or revertant viruses, and MG-1A12 staining (post-fusion) was stronger. Thus, the premature capsid release of gL− virions reflected gH being in its down-stream gH-only form from the start, and gB engaging prematurely in membrane fusion after endocytosis.

Bottom Line: However, gH switched back to a gL-independent conformation after virion endocytosis.This switch coincided with a conformation switch in gB and with capsid release.Virions lacking gL constitutively expressed the down-stream form of gH, prematurely switched gB to its down-stream form, and showed premature capsid release with poor infectivity.

View Article: PubMed Central - PubMed

Affiliation: Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT
The glycoprotein H (gH)/gL heterodimer is crucial for herpesvirus membrane fusion. Yet how it functions is not well understood. The Murid Herpesvirus-4 gH, like that of other herpesviruses, adopts its normal virion conformation by associating with gL. However, gH switched back to a gL-independent conformation after virion endocytosis. This switch coincided with a conformation switch in gB and with capsid release. Virions lacking gL constitutively expressed the down-stream form of gH, prematurely switched gB to its down-stream form, and showed premature capsid release with poor infectivity. These data argue that gL plays a key role in regulating a gH and gB functional switch from cell binding to membrane fusion.

Show MeSH
Related in: MedlinePlus