<P> The L RNA encodes the L protein, which functions as the viral transcriptase / replicase . Within virions, the genomic RNAs of hantaviruses are thought to complex with the N protein to form helical nucleocapsids, the RNA component of which circularizes due to sequence complementarity between the 5' and 3' terminal sequences of genomic segments . </P> <P> As with other Bunyaviridae, each of the three segments has a consensus 3' - terminal nucleotide sequence (AUCAUCAUC), which is complementary to the 5' terminal sequence and is distinct from those of the other four genera in the family . These sequences appear to form panhandle structures which seem likely to play a role in replication and encapsidation facilitated by binding with the viral nucleocapsid (N) protein . The large segment is 6530 - 6550 nucleotides (nt) in length, the medium is 3613 - 3707 nt in length and the small is 1696 - 2083 nt in length . </P> <P> No nonstructural proteins are known unlike the other genera in this family . At the 5' and 3' of each segment are short noncoding sequences: the noncoding segment in all sequences at the 5' end is 37 - 51 nt . The 3' noncoding regions differ: L segment 38 - 43 nt; M segment 168 - 229 nt; and S segment 370 - 730 nt . The 3' end of the S segment is conserved between the genera suggesting a functional role . </P> <P> Hantavirus virions are about 120 - 160 nanometers (nm) in diameter . The lipid bilayer of the viral envelope is about five nm thick and is embedded with viral surface proteins to which sugar residues are attached . These glycoproteins, known as Gn and Gc, are encoded by the M segment of the viral genome . They tend to associate (heterodimerize) with each other and have both an interior tail and an exterior domain that extends to about six nm beyond the envelope surface . </P>

What is the name of the two filoviruses that originated in africa