Alphavirus RNA replicase is located on the cytoplasmic surface of endosomes and lysosomes.
Using morphological and cell biological techniques, we have shown that the RNA replicase of Semliki Forest and Sindbis virus (two closely related alphaviruses) is located in complex ribonucleoprotein structures associated with the cytoplasmic surface of modified secondary lysosomes and endosomes. These nucleoprotein complexes often form a bridge between the membrane of the endocytic vacuole and the rough endoplasmic reticulum where the synthesis of the structural proteins of these viruses occurs. The results suggest that these cytopathic vacuoles constitute sites not only for viral RNA synthesis, but also for translation of structural proteins, and for the assembly of nucleocapsids.
Froshauer
S
S
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510.
Kartenbeck
J
J
Helenius
A
A
D000524:Alphavirus / Q000201:enzymology / Q000254:growth & development*; D000818:Animals; D002451:Cell Compartmentation; D002460:Cell Line; D004705:Endocytosis; D011992:Endosomes / Q000201:enzymology* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D008247:Lysosomes / Q000201:enzymology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D011233:Precipitin Tests; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012367:RNA, Viral / Q000096:biosynthesis*; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D014617:Vacuoles / Q000201:enzymology / Q000648:ultrastructure; D014779:Virus Replication
D012367:RNA, Viral; D012261:Ribonucleoproteins; D012316:RNA Nucleotidyltransferases; D012324:RNA-Dependent RNA Polymerase