Specific transcription of a 15-kilodalton zene gene in HeLa cell extracts

A maize genomic clone containing a 15 kilodalton zein gene was used as a template in an in vitro transcription system for HeLa cells. A runoff assay indicated transcription was initiating 5' to the map position of the open reading frame for the protein. Fine-structure mapping of RNAs synthesized in vitro showed two transcription start sites separated by 24 bases. One start site is 27 bases downstream of a consensus TATA sequence; the other is 30 bases downstream of a TATG sequences. The initiation sites for RNA synthesized in vitro map to the same region of the genomic clone as zein RNA isolated from developing maize kernels.