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DTSTAMP:20260405T054140Z
UID:1717750800@ist.ac.at
DTSTART:20240607T110000
DTEND:20240607T120000
DESCRIPTION:Speaker: Harmit Malik\nhosted by Beatriz Vicoso\nAbstract: The 
 evolutionary battle between viruses and the immune system is a high-stakes
  arms race. The immune system makes antiviral proteins\, called restrictio
 n factors\, which can stop the virus from replicating. In response\, virus
 es evolve to evade the effects of restriction factors. To counter this\, r
 estriction factors evolve too\, and the cycle continues\, in which both si
 des rapidly evolve at interaction interfaces to gain or evade immune defen
 se. For example\, primate TRIM5α uses its rapidly evolving ‘v1’ loop 
 to bind retroviral capsids whereas the MxA antiviral protein uses its rap
 idly evolving Loop L4 domain to recognize viruses such as influenza\; sing
 le mutations in these loops can dramatically improve viral restriction. Th
 e challenge for the immune system is that mammals do not evolve as fast as
  viruses. How then\, in the face of this disadvantage\, can the immune sys
 tem hope to keep pace with viral evolution? Using deep mutational scanning
 \, we comprehensively measured how single mutations in the TRIM5α v1 loop
  affect restriction of divergent retroviruses. Unexpectedly\, we found tha
 t most mutations increase weak antiviral function. Moreover\, most random 
 mutations do not disrupt potent viral restriction\, even when it is newly 
 acquired via a single adaptive substitution. Our results indicate that TRI
 M5α’s adaptive landscape is remarkably broad and mutationally resilient
 \, exploiting both missense and indel mutations\, maximizing its chances o
 f success in evolutionary arms races with retroviruses. We also exploit co
 mbinatorial mutagenesis at rapidly evolving positions to dissect and enhan
 ce the antiviral properties of MxA antiviral proteins\, revealing unprec
 edented capacity for antiviral adaptation and a 'breath versus specificity
 ' tradeoff that constrains their natural evolution
LOCATION:Raiffeisen Lecture Hall\, ISTA
ORGANIZER:maria.arias.sutil@ista.ac.at
SUMMARY:Harmit Malik:  Rules of engagement: molecular arms races between ho
 st and viral genomes.
URL:https://talks-calendar.ista.ac.at/events/4252
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