The paramyxovirus genome, a nonsegmented, negative-polarity, single-stranded RNA of approximately 15 kb, contains six transcription units flanked at the 3' and 5' ends by a short (approximately 50- to 60- @entity377 ) extracistronic sequence, dubbed the positive and negative leader regions. These leader template regions, present at the 3' end of the genome and the antigenome, have been shown to contain essential signals governing RNA replication activity. Whether they are sufficient to promote replication is still open to question. By using a series of @entity7686 defective interfering RNAs carrying a nested set of deletions in the promoter regions, it is shown here that for both the genomic and antigenomic promoters, a 3'-end RNA sequence of 96 @entity2036 is required to allow replication. Sequence comparison of active and inactive promoters led to the identification of a set of three @entity377 hexamers ( @entity2036 79 to 84, 85 to 90, and 91 to 96) containing a repeated motif RXXYXX [shown as 5'-3' positive-strand]. Sequential mutation of each hexamer into its complementary sequence confirmed their essential role. The three hexamers are required, and their relative positioning is important, since displacing them by 6 @entity2036 destroyed promoter function. RNAs carrying degenerate @entity2036 in the three hexamers were used as replication templates. They led to the selection of actively replicating RNA species exclusively carrying the basic motif (GNNNNN)3 from @entity2036 79 to 96. These results clearly show that, apart from the region from @entity2036 1 to 31, previously identified as governing @entity7686 replication activity, a second element, spanning at the most @entity2036 79 to 96, appears essential. Thus, the paramyxovirus replication promoters are not confined to the leader template regions, as seems to be the case for the rhabdoviruses.

The activity of XXXX genomic and antigenomic promoters requires a second element past the leader template regions: a motif (GNNNNN)3 is essential for replication.

@entity377 :: ('CHEBI:36976', 'Chemical') :: ['nucleotide'] @entity7686 :: ('11191', 'Species') :: ['Sendai virus'] @entity2036 :: ('MESH:D009711', 'Chemical') :: ['nucleotides']
@entity7686 :: (11191,Species) :: ['Sendai virus']
