The E1B transcription map of the enteric adenovirus type 41

Enteric adenovirus type 41 (Ad41) is defective for growth in conventional established cell lines. Ad41 is dependent on the Ad5 early regions E1A/E1B since it cannot grow in HEK cells but only in 293 HEK cells transformed by Ad5 E1 region. However, Hep-2 cells have also been shown to support the growth of Ad41 to some extent. The nucleotide sequence of the E1B region of the Ad41 strain D389 has been determined. When compared to the corresponding region of the Ad41 prototype strain (Tak) the degree of homology in the DNA sequences was close to 100%. The mRNAs from the E1B region of the Ad41 strain D389 have been studied by Northern blot, primer extension, and polymerase chain reaction-cDNA analysis. E1B transcripts corresponding to Ad2 14 S, 22 S, and 9 S mRNAs were identified but no 13 S mRNA equivalent was detected, a pattern similar to that seen in the Ad40 and Ad12 transcription maps. However, the Ad41 E1B 14S mRNA equivalent has one additional small exon of 23 nucleotides, created by a donor and an acceptor splice site located at positions not seen in other E1B transcripts of human adenoviruses analyzed so far. The coding potential for E1B 19K, 55K, and 15K proteins and for pIX is retained in the Ad41 transcripts. In contrast to other adenoviruses, except for the closely related Ad40, the ORF of pIX starts in the intron of the 22 S mRNA.