Near-upstream element

Fig. 3 Different methods were used to extract features from different regions of the poly(A) signals. NUE near upstream element, CS cleavage site, PSSM position-specific scoring matrix, P/V probability based on first-order inhomogeneous Markov sub-model...

Fig.1 The RNA used as in vitro cleavage substrates in this study. STS and its extension variants from original sequence are depicted as bars with different nucleotide length indicated on the top. These fragments can be PCR-amplified from the CaMV 35S 3 -end region. The black boxes indicate conserved cis-element (Wf far-upstream element, NUE near-upstream element, vert/ca/arrow cleavage site) while the wftrfe toes indicate sequences between them AAAAAA. represents the poly(A) tail...

An increase in the basal transcription activity originating from the promoter requires regulatory DNA sequences. These sequences can be proximally or distaUy located and serve as binding sites for transcriptional activators. The cis-acting DNA elements can be found near the promoter in either orientation. They are often termed upstream activating sequences" (UAS). Regulatory sequences can also be located far from the promoter. Their effect is independent of their orientation and they are known as enhancers. 

The book Gas Turbine Performance by Walsh and Fletcher [10] has excellent treatment on turbomachineiy maps. An example of a compressor map is shown in Figure 8.10. This map fully defines the pressure-flow-efficiency-rotational speed relationship of the compressor. Employing the Beta-line or R-line method, maps can be digitized into tabular form as described by Walsh and Fletcher [10], The Betaline method is helpful to ensure numeric stability with such maps that would be otherwise problematic because of the near zero and infinite slope at the ends of the constant speed lines. Note that the compressor model can either be a flow element or a pressure element. That is, from speed and pressure it is possible to obtain flow and efficiency from the map, or from speed and flow it is possible to obtain pressure and efficiency from the map. The choice depends on what is more convenient, that is, what type of elements are modeled upstream and downstream. 

However, it is now clear that some upstream promoter elements and enhancers show strong similarities physically and functionally so that the distinction is not as clear as was once thought. For enhancers located a long distance away from the gene being controlled, interaction between transcription factors bound to the enhancer and to promoter elements near the gene occurs by looping out of the DNA between the two sets of elements (Fig. 2). 

Boland, R., Minghetti, P.P., Lowe, K.E. Norman, A.W. (1991). Sequences near the CCAAT region and putative 1,25 dihydroxyvitamin Dj response element and further upstream novel regulatory sequences of calbindin D28K promoter show DNAse I footprinting protection. Mol Cell Endocrinol, 75, 57-63. 

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