Replication

The ebolavirus life cycle begins with virion attachment to specific cell surface receptors, followed by fusion of the virion envelope with cellular membranes and the concomitant release of the virus nucleocapsid into the cytosol. The viral RNA polymerase, encoded by the L gene, partially uncoats the nucleocapsid and transcribes the genes into positive strand mRNAs, which are then translated into structural and nonstructural proteins. Ebolavirus RNA polymerase (L) binds to a single promoter located at the 3 end of the genome. Transcription either terminates after a gene or continues to the next gene downstream. This means that genes close to the 3 end of the genome are transcribed in the greatest abundance, whereas those toward the 5 end are least likely to be transcribed. The gene order is, therefore, a simple but effective form of transcriptional regulation. The most abundant protein produced is the nucleoprotein, whose concentration in the cell determines when L switches from gene transcription to genome replication. Replication results in full length, positive strand antigenomes that are, in turn, transcribed into negative strand virus progeny genome copy. Newly synthesized structural proteins and genomes self assemble and accumulate near the inside of the cell membrane. Virions bud off from the cell, gaining their envelopes from the cellular membrane they bud from. The mature progeny particles then infect other cells to repeat the cycle.The Ebola Virus genetics are difficult to study due to its virulent nature.