Plant expression signals of the Agrobacterium T-cyt gene.

Within the 5' and 3' non-coding regions of the T-cyt gene from the octopine T-DNA of Agrobacterium tumefaciens sequences required for expression of this gene in plant cells were identified by deletion mutagenesis. The results show that 184 bp of the 5' non-coding region and 270 bp of the 3' non-coding region are sufficient for wild-type expression. Within the 5' non-coding region two essential expression signals were identified: (1.) an activator element located between -185 and -129 with respect to the ATG start codon and (2.) one out of two TATA boxes. Deletions of the activator element or the two TATA boxes resulted in nonfunctional genes. Deletion of the upstream TATA box and both putative CAAT boxes did not significantly affect expression. Within the 3' non-coding region, the polyadenylation box most distal to the stop codon was not essential for expression, but sequences more upstream, including a second polyadenylation box were found to be required for wild-type expression.     

Positive and negative regulatory DNA elements including a CCArGG box are involved in the cell type-specific expression of the human muscle dystrophin gene.

The muscle-specific promoter of the dystrophin gene is active in skeletal, cardiac, and smooth muscles and is specifically stimulated during differentiation of myoblasts into multinucleated myotubes. An 850-base pair (bp) DNA fragment upstream from the cap site is able to confer a partial muscle specificity to a reporter gene. The region between -850 and -140 bp includes nonspecific negative and positive regulatory sequences. A continuous stretch of 140 bp upstream from the cap site exhibits a striking conservation between rodents and human (93% homology) and still retains muscle preference of expression. It contains two putative binding sites for factors involved in regulation of other muscle-specific genes, a CCArGG box and an E box. This latter element, however, is unable to confer the ability to be transactivated by MyoD1 to the dystrophin promoter. The -140-bp promoter fragment exhibits antagonist effects contributed by one inhibiting sequence (nucleotide -140/-96), active in all cell types, and one activating region, from nucleotide -96 to the cap site, sufficient to confer a muscle preference of expression, in which the CCArGG box seems to play a major role.     

Binding sites of HeLa cell nuclear proteins on the upstream region of adenovirus type 5 E1A gene.

Twenty one binding sites of HeLa cell nuclear proteins were identified on the upstream region of adenovirus type 5 E1A gene using DNase I footprint assay. The proximal promoter region contained five binding sites that overlapped the cap site, TATA box, TATA-like sequence, CCAAT box, and -100 region relative to the E1A cap site(+1). The -190 region was a potential site for octamer-motif binding proteins, such as NFIII and OBP100. An upstream copy of the E1A enhancer element 1 was the site for a factor (E1A-F) with the binding specificity of XGGAYGT (X = A, C; Y = A, T). E1A-F factor also bound to three other sites, one of which coincided with the distal E1A enhancer element. The distal element also contained a potential site for ATF factor. The adenovirus minimal origin of DNA replication competed for DNA-protein complex formation on the CCAAT and TATA box region and the -190 region, suggesting that these regions interacted with a common or related factor.