Elements modulating the block of transcription elongation at the adenovirus 2 attenuation site.
We have previously reported that a block of transcription elongation is functioning in vivo and in vitro within the leader sequences of SV40 and the adenovirus 2 major late transcription units and in the regulation of transcription of the P4 promoter of minute virus of mice. In the present study using the HeLa whole cell extract-Sarkosyl system with adenovirus 2 major late promoter as a template we have analyzed several basic parameters that can contribute to our understanding of the mechanism that regulates the elongation block at the adenovirus 2 attenuation site. We show that the elongation block is augmented at elevated temperatures (40-45 degrees C). The elongation block can be reversed by the addition of 0.2 M NaCl to the transcription reaction and the reversibility is temperature-dependent. Furthermore, while at 30-35 degrees C the elongation block is reversible with dilution of the Sarkosyl, at 40-45 degrees C it is only partially reversible. These results may indicate that a factor(s) is involved in the regulation of the elongation block and/or that the conformation of the transcription complex is temperature dependent. Finally, we show that the extent of the elongation block is dependent on the consecutive T residues at the attenuation site and we discuss the involvement of RNA secondary structure in eliciting the elongation block.
Kessler
M
M
Department of Genetics, Weizmann Institute of Science, Rehovot, Israel.
Ben-Asher
E
E
Aloni
Y
Y
D000260:Adenoviruses, Human / Q000235:genetics*; D001483:Base Sequence; D002872:Chromosome Deletion; D005814:Genes, Viral; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D013696:Temperature; D013816:Thermodynamics; D014158:Transcription, Genetic
D012367:RNA, Viral