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DTSTAMP:20260424T040528Z
UID:1738578600@ist.ac.at
DTSTART:20250203T113000
DTEND:20250203T123000
DESCRIPTION:Speaker: Karolin Luger\nhosted by Alicia Michael\nAbstract:  A
 ll eukaryotes organize their DNA into nucleosomes\, consisting of an octam
 er of the four core histones H2A\, H2B\, H3\, and H4\, around which 147 ba
 se pairs of DNA are wrapped in two tight superhelical turns. Histones were
  an early acquisition in eukaryogenesis that allowed for massive genome ex
 pansion\, a prerequisite for the complexity observed in modern-day eukaryo
 tes. Histones are the targets of epigenetic modifications through the inco
 rporation of histone variants and histone post-translational modifications
 \, and require elaborate assembly and remodeling machinery for gene regula
 tion. Who provided the chromatin starter kit to the early eukaryote? Many 
 archaea organize their genomes with single\, non-diversified histones that
  form slinky-like structures\, without the requirement for additional mach
 inery to assemble and disassemble nucleosomal structures.  We hypothesize
  that these histones serve protective rather than regulatory functions and
  reflect adaptation to the often-extreme environment\, and that different 
 histone ‘strategies’ have evolved for different life styles. A subclas
 s of giant viruses (ancient double-stranded DNA viruses that infect mostly
  amoebae) also encode their own histones\, and these form meta-stable nucl
 eosome-like structures with distinct features. Some additionally encode hi
 stone variants and linker histones\, and histones can be fused in various 
 combinations. Unexpectedly\, we recently discovered that histones are spor
 adically present in the bacterial domain of life. In a stunning reversal o
 f ‘histone logic’\, these small histones can encase straight DNA rathe
 r than wrapping it around them.  As such\, histones are no longer a prero
 gative of eukaryotes but appear to be an ancient DNA packaging principle t
 hat has adapted to varying constraints in different domains of life.
LOCATION:RLH\, ISTA
ORGANIZER:maria.arias.sutil@ista.ac.at
SUMMARY:Karolin Luger: The Rapidly Expanding Histone Universe 
URL:https://talks-calendar.ista.ac.at/events/5109
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