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SUMMARY:New insights into pneumococcal biology from dual RNA-seq\, Tn-seq 
 and CRISPRi approaches
DTSTART:20170530T121500
DTSTAMP:20260427T230505Z
UID:ab06f7452ad9b62cb808733752b7d08cfb809826350ad85623b5cb3d
CATEGORIES:Conferences - Seminars
DESCRIPTION:Jan-Willem Veening\, Department of Fundamental Microbiology (D
 MF)\, UNIL\, Switzerland\nStreptococcus pneumoniae\, the pneumococcus\, is
  the main etiological agent of pneumonia. Pneumococcal infection is initia
 ted by bacterial adherence to lung epithelial cells. To uncover the exact 
 transcriptional changes that occur in both host and microbe during infecti
 on\, we developed a time-resolved dual RNA-seq model. By comparing transcr
 iptional changes between wild-type encapsulated and mutant unencapsulated 
 pneumococci\, we demonstrate that adherent pneumococci\, but not free-floa
 ting bacteria\, repress innate immune responses in epithelial cells. Inter
 estingly\, many genes of unknown function were differentially expressed du
 ring adherence to human cells. To systematically perform functional analys
 is on these ‘unknown’ genes\, we created a knockdown library targeting
  348 potentially essential genes by CRISPR interference (CRISPRi) and show
  a growth phenotype for 254 of them (73%). Using high‐content microscopy
  screening and functional analysis\, we identified and characterized sever
 al new genes involved in cell wall biosynthesis and competence development
 . Finally\, we systematically tagged every essential protein of unknown f
 unction to a monomeric superfolder-GFP. By combining Tn-Seq\, CRISPRi and 
 GFP-localization data\, we identified CcrZ (Cell Cycle Regulator protein 
 Z)\, which co-localizes with FtsZ and is highly conserved in Streptococci.
  Marker frequency analysis\, suppressor analysis and chromosome labeling e
 xperiments showed that\, in absence of CcrZ\, daughter chromosomes are not
  properly segregated prior to cell division. Together\, these findings ind
 icate that CcrZ acts as a link between DNA replication\, chromosome segreg
 ation and cell division.\nhttp://wp.unil.ch/veeninglab/
LOCATION:SV 1717 https://plan.epfl.ch/?room==SV%201717
STATUS:CONFIRMED
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