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UID:20260708T074644EDT-1381nbdITX@132.216.98.100
DTSTAMP:20260708T114644Z
DESCRIPTION:Dr. Jeffrey Wilusz\nProfessor\nColorado State University\nDepar
 tment of Microbiology\, Immunology & Pathology\n \n“How Viral RNAs Escape 
 the Wrath of the Cellular RNA Decay\nMachinery during Infection”\n \n \nTh
 e mechanisms utilized by viruses to protect their transcripts\nfrom the ce
 llular RNA decay machinery\, as well as the biological\nrelevance of this 
 protection\, are largely unexplored.  We have\nfound that Sindbis virus\, 
 and likely other alphaviruses\, use U-rich\n3’ UTR sequences in their capp
 ed and polyadenylated RNAs to recruit\nthe cellular HuR protein during inf
 ections of both human and\nmosquito cells.   HuR binds viral RNAs with hig
 h\nspecificity and affinity.  Furthermore\, Sindbis virus induces\nthe sel
 ective movement of HuR protein out of the nucleus of\nmammalian cells duri
 ng infection thereby increasing the cytoplasmic\npool of the protein avail
 able to the virus.  Finally\,\nknockdown of HuR results in a significant i
 ncrease in the rate of\ndecay of Sindbis virus RNAs and diminishes viral y
 ields in both\nhuman and mosquito cells.  Collectively these data indicate
 \nthat Sindbis virus\, and likely other alphaviruses\, usurp the HuR\nprot
 ein to avoid the cellular mRNA decay machinery and maintain a\nhighly prod
 uctive infection.\nWe have also explored the relationship between the cell
 ular mRNA\ndecay machinery and two other RNA viruses.  Our results\nsugges
 t that non-polyadenylated flavivirus RNAs may repress the\nmajor 5’-3’ pat
 hway of cellular mRNA decay during infections via a\ndirect inhibition of 
 the XRN1 5’-3’ exoribonuclease\, perhaps\ncontributing to viral pathogenes
 is.  Data on Rabies virus\, a\nnegative sense RNA virus\, suggest that the
  relative stability of\nits mRNAs\, in addition to the previously describe
 d efficiency of\ntranscription via start-stop polymerase initiation\, may 
 play an\nimportant role in regulating the level of select viral mRNAs duri
 ng\ninfection.\n \n \nReferences\nBergman\, N\, Moraes KCM\, Anderson\, J.
 R.\, Zaric\, B.\, Kambach\, C\,\nSchneider\, R.J.\, Wilusz\, C.J. and Wilu
 sz J.  (2007)  Lsm\nproteins bind to and stabilize RNAs containing 5’ poly
 (A)\ntracts.  Nature Struct Mol. Biol.\,  14: 824-831.\n \nGarneau\, N.L.\
 , Sokoloski\, K\, Opyrchal\, M\, Neff\, C.P.\, Wilusz\,\nC.J. and Wilusz\,
  J.  (2008).  The 3’ untranslated region\nof sindbis virus represses the d
 eadenylation of viral transcripts\nin mosquito and mammalian cells.  J. Vi
 rol. 82: \n880-892.\n \nSokoloski\, K\, Dickson\, A\, Chaskey E.L.\, Garne
 au\, N.L.\, Wilusz\,\nC.J. and Wilusz\, J.  (2010).  Sindbis virus usurps 
 the\ncellular HuR protein to stabilize its transcripts and promote\nproduc
 tive infections in mammalian and mosquito cells.  In\nRevision\n
DTSTART:20100329T160000Z
DTEND:20100329T160000Z
LOCATION:McIntyre Medical Building\, CA\, QC\, Montreal\, H3G 1Y6\, 3655 pr
 omenade Sir William Osler
SUMMARY:Biochemistry Seminar
URL:/channels/event/biochemistry-seminar-115234
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