Characterization of the L gene and 5 ' trailer region of Ebola virus

The nucleotide sequences of the L gene and 5' trailer region of Ebola virus strain Mayinga (subtype Zaire) have been determined, thus completing the s equence of the Ebola virus genome. The putative transcription start signal of the L gene was identical to the determined 5' terminus of the L mRNA (5' GAGGAAGAUUAA) and showed a high degree of similarity to the corresponding regions of other Ebola virus genes. The 3' end of the L mRNA terminated wit h 5' AUUAUAAAAAA, a sequence which is distinct from the proposed transcript ion termination signals of other genes. The 5' trailer sequence of the Ebol a virus genomic RNA consisted of 676 nt and revealed a self-complementary s equence at the extreme end which may play an important role in virus replic ation. The L gene contained a single ORF encoding a polypeptide of 2212 aa, The deduced amino acid sequence showed identities of about 73 and 44% to t he L proteins of Ebola virus strain Maleo (subtype Sudan) and Marburg virus , respectively. Sequence comparison studies of the Ebola virus L proteins w ith several corresponding proteins of other non-segmented, negative-strand RNA viruses, including Marburg viruses, confirmed a close relationship betw een filoviruses and members of the Paramyxovirinae. The presence of several conserved linear domains commonly found within L proteins of other members of the order Mononegavirales identified this protein as the RNA-dependent RNA polymerase of Ebola virus.