title: Transcription of cloned actin genes of Dictyostelium discoideum in the cell-free system.
abstract: Truncated templates of a cloned actin gene (actin 5) of Dictyostelium discoideum were transcribed in a HeLa cell extract from a position indistinguishable from the in vivo initiation site. The efficiency of this accurate transcription, however, was very low compared with that of the adenovirus 2 major late gene in the same system. Transcription of the actin 6 and 8 genes, of which the 5'-flanking regions differ in their base sequences from the corresponding region of the actin 5 gene, was not good in either fidelity or efficiency. When the partially purified RNA polymerase II of D. discoideum was used instead of the HeLa cell extract, no accurate transcription of the actin 5 gene occurred. However, simultaneous addition of RNA polymerase II and HeLa cell extract into the cell-free system caused a shift of the in vitro initiation point of transcription of the actin 5 gene to a position about 20 nucleotides downstream from the presumed in vivo initiation site. The reason for the shift remains unknown, but it is supposed that some factor(s) other than RNA polymerase II are involved in the accurate initiation of transcription and the maintenance of transcription efficiency of the actin genes.
mesh_terms: D000199:Actins / Q000235:genetics*; D000260:Adenoviruses, Human / Q000235:genetics; D002474:Cell-Free System; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004023:Dictyostelium / Q000235:genetics*; D005796:Genes; D005814:Genes, Viral; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D012319:RNA Polymerase II / Q000302:isolation & purification / Q000378:metabolism; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics
chemical_list: D000199:Actins; D014764:Viral Proteins; D012319:RNA Polymerase II; D004262:DNA Restriction Enzymes