Flavivirus genome organization, expression, and replication.

OVERVIEW............................................................................................ 650 INTRODUCTION TO FLA VIVIRUS BIOLOGy.............................................. 650 Classification and Life Cycle in Nature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 Importance as Disease Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 1 Replication in Cultured Cells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 652 ORGANIZATION AND TRANSLATION OF THE GENOME RNA ..................... 653 General Features ............................................ ..................................... 653 Translation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 PROTEOLYTIC PROCESSING OF THE VIRAL POLYPROTEIN........................ 655 The StruclUra[ Proteins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658 The Nonstructural Proteins . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . .. 658 PROPERTIES OF VIRAL PROTEINS ........................................................... 660 Structural Proteins. . . ... . . . . . . . .... . . .. . . . . . . . . ... . . . . . . . ... .. . . . . . . . . . ...... . . . . . . . . . . . ..... . . . . . 660 Nonstructural Proteins........................................................................... 667 VIRION STRUCTURE AND ASSEMBLy...................................................... 671 CONSERVED RNA SEQUENCES AND STRUCTURES.................................... 673 5' and 3' Terminal Secondary Structures ................................................... 674 Conserved and Repeated Sequences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 675 RNA REPLICATION .................... . .................. ......................................... 675