English: Replication cycle of filoviruses (possibly excluding striaviruses and thamnoviruses). Virions attach to cell-surface attachment factors (orange Ys) and are taken into the cell via endocytosis. The filovirion glycoproteins (yellow clubs) bind to endosomal Niemann-Pick disease, type C1 (NPC1, white zigzag) catalyze the fusion of viral and cellular membranes to release the filovirus RNP complex (green helix). The polymerase complex (consisting of VP35 [purple dots] and L [blue semicircles]) transcribes filovirus mRNAs that are translated into filovirus proteins and replicates filovirus genomic RNA via antigenomic intermediates. Genomic RNA and antigenomic RNA occur only as ribonucleoprotein complexes which serve as templates for replication and/or transcription. Assembly of filoviral proteins and progeny genomes occurs in the cytoplasm and results in budding of progeny virions at the plasma membrane.