Inhibition of Retrovirus Replication by Human Schlafen 11

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Inhibition of Retrovirus Replication by Human
Schlafen 11
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Murine Schlafen (Slfn) Family
In search for IRF3-regulated genes, we found
multiple members of the Schlafen (Slfn) gene
family
Putative RNA helicase domain
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Human Slfn Family
Putative AAA domain
Putative RNA helicase domain
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Discovery of Slfns

• The Schlafen (Slfn) family of genes are
  differentially regulated during thymocyte
  maturation and are preferentially expressed in
  the lymphoid tissues.
• Ectopic expression of the prototype member Slfn1
  early in the T lineage alters cell growth and
  development.
• Expression of Slfn1 in fibroblasts and thymoma
  cells either retards or ablates cell growth.
• Slfn1 knockout mice had no significant phenotype

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In the next 12 years

• Transgenic T-cell specific expression of muSlfn8
  in mice resulted in impaired T cell development
  (Geserick et al., Int Immunol. 2004)
• Mutation of muSlfn2 causes loss of immune
  quiescence in T cells and monocytes(Berger et
  al., Nature Immun. 2010)
• muSlfn1 causes a cell cycle arrest by inhibiting
  induction of cyclin D1 (Brady et al., JBC 2005)
• Role of Schlafen 2 (SLFN2) in the generation of
  interferon alpha-induced growth inhibitory
  responses (Katsoulidis et al., JBC 2009)
• Lack of reproducible growth inhibition by muSlfn1
  and muSlfn2 in vitro (Zhao et al., Blood Cells
  Mol Dis. 2008)

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AAA-domain
ATPases Associated with various cellular
Activities

• membrane fusion
• protein translocation
• ER-associated degradation
• proteolysis
• peroxisome biogenesis
• mitosis, meiosis
• apoptosis
• microtubule dynamics
• motors
• DNA replication
• DNA recombination and repair
• transcriptional regulation
• homo/hetero-multimer formation

Snider et al. Genome Biology 2008 9216
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Slfn expression profiles
mRNA Levels of Slfns in Human Fibroblasts (HFF)
upon Stimulation
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huSlfn11 knock-down HEK293 cell lines
Slfns are induced by Interferons and TLR
ligands Putative helicase domain (similarity to
RIG-I ??) gt Do they function as pathogen
sensors or activators of innate immune responses?
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Retroviral Replication Cycle
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huSlfn11 does not alter Infection by MSCV or HIV
MSCV
HIV
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HIV Infection and Replication Cycle
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huSlfn11 restricts production of MSCV or HIV
MSCV
HIV
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Truncation mutants of huSlfn11
RNA helicase
Divergent AAA domain
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huSlfn11N restricts production of MSCV or HIV
MSCV
HIV
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huSlfn11 does not restrict production of AAV or
HSV
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Mechanism?
Extracellular p24 and vRNA levels correlate with
viral titers by infection assay gt Fewer viral
particles are produced
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Virus budding release are not affected by
huSlfn11
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Intracellular vRNA levels are not affected by
huSlfn11
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huSlfn11 specifically inhibits viral protein
synthesis
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huSlfn11 specifically inhibits viral protein
synthesis
huSlfn11 appears to inhibit viral protein
translation by interference with -1 frameshifting

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CEM cells and HIVLAI
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THANKS...
David Lab
Salk Institute
Manqing Li Hilary Sandig Elaine Kao Kirsten
Vroom Irene Pedersen Dennis Otero Hiroshi Moro
Yoshinari Tanabe Takeaki Nishibori
Matt Weitzmann Sebastian Landry John Young
UCSD-CFAR
John Guatelli Davey Smith
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