?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8628%2F&rft.title=Mechanisms+by+which+Nonnucleoside+Reverse+Transcriptase+Inhibitors+Block+HIV-1+Replication+Alone+and+in+Combination+with+other+Reverse+Transcriptase+Inhibitors&rft.creator=Radzio%2C+Jessica+Ann&rft.description=Inhibition+of+reverse+transcriptase+(RT)+is+a+vital+tactic+in+the+prevention+of+human+immunodeficiency+virus+1+(HIV-1).+Nonnucleoside+reverse+transcriptase+inhibitors+(NNRTIs)+are+a+class+of+compounds+demonstrated+to+act+as+allosteric+inhibitors+of+RT+DNA+polymerization.+However%2C+several+lines+of+evidence+suggest+that+polymerization+may+not+be+the+main+mechanism+of+inhibition+of+reverse+transcription.+It+has+been+demonstrated+that+NNRTIs+also+have+the+ability+to+modulate+RT+ribonuclease+(RNase)+H+cleavage.+Additionally%2C+recent+evidence+suggests+that+resistance+to+chain-terminating+nucleoside+reverse+transcriptase+inhibitors+(NRTIs)+is+dependent+on+a+balance+between+the+polymerase+and+RNase+H+activities+of+the+enzyme.+In+light+of+this%2C+I+hypothesize+that+NNRTIs+block+reverse+transcription+by+exerting+effects+on+both+the+DNA+polymerase+and+RNase+H+active+sites+of+the+enzyme%2C+significantly+disrupting+the+equilibrium+between+these+two+enzymatic+activities.+Therefore%2C+the+ability+for+NNRTIs+to+be+combined+with+other+classes+of+RT+inhibitors+in+antiretroviral+therapies+will+depend+on+how+these+compounds+respond+to+the+NNRTI-induced+shift+in+the+polymerase%2FRNase+H+activity+equilibrium.+This+study+demonstrates+that+NNRTIs+cause+the+accelerated+appearance+of+secondary+RNase+H+cleavage+products+that+have+decreased+RNA%2FDNA+hybrid+structures.+As+a+result%2C+these+template%2Fprimers(T%2FPs)+are+not+sufficient+substrates+for+NRTI+removal+and+therefore%2C+excision+is+less+efficient+in+the+presence+of+NNRTIs.+Additionally%2C+fluorescent+resonance+energy+transfer+experiments+demonstrate+that+NNRTIs+cause+a+shift+in+the+binding+of+RT+and+T%2FP+such+that+the+RNase+H+domain+is+moved+away+from+the+5'end+of+the+primer.+Finally%2C+subunit-specific+analysis+shows+that+resistance+to+RTI+combination+therapy+facilitated+by+the+N348I+mutation+is+a+result+of+effects+from+the+p51+subunit.+I+propose+that+the+binding+of+NNRTIs+cause+RT+to+bind+to+T%2FP+in+a+polymerase-incompetent+mode%2C+resulting+in+decreased+polymerization+and+shorted+RNase+H+cleavage+products.+Additionally%2C+N348I+can+facilitate+dual+resistance+by+favoring+the+polymerase-competent+binding+mode.+This+work+is+of+public+health+significance+because+it+lays+the+foundation+for+the+development+of+new+reverse+transcriptase+inhibitors+and+highlights+the+importance+of+resistance+in+the+connection+domain+of+HIV-1+RT.&rft.date=2010-09-29&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8628%2F1%2FRADZIO_ETD_2010.pdf&rft.identifier=++Radzio%2C+Jessica+Ann++(2010)+Mechanisms+by+which+Nonnucleoside+Reverse+Transcriptase+Inhibitors+Block+HIV-1+Replication+Alone+and+in+Combination+with+other+Reverse+Transcriptase+Inhibitors.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++