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.