Promoter core module

The DNA part of each control module can be divided into three main regions, the core or basal promoter elements, the promoter proximal elements and the distal enhancer elements (Figure 9.1). The best characterized core promoter element is the TATA box, a DNA sequence that is rich in A-T base pairs and located 25 base pairs upstream of the transcription start site. The TATA box is recognized by one of the basal transcription factors, the TATA box-binding protein, TBP, which is part of a multisubunit complex called TFIID. This complex in combination with RNA polymerase 11 and other basal transcription factors such as TFIIA and TFIIB form a preinitiation complex for transcription. 

The core promoter module can be defined functionally by its capability to assemble the transcription initiation complex (see Figure 4.3) and orient it specifically towards the TSS of the promoter [13], defining the exact location of the TSS. Various combinations of about four distinguishable core promoter elements that constitute a general core promoter can achieve this. This module includes the TATA box, the initiator region (INR), an upstream activating element, and a downstream element. (The TATA box is a basic... 

Basically, at least the four different core promoter types detailed above have been identified so far, which all represent valid combinations of core promoter sites (reviewed in [17]). If the combinations involving upstream and downstream elements are also considered, a total of 7 possible core promoter modules are possible (most of which can be actually found in genes and consist of the four variants in Figure 4.2 adding upstream or downstream elements or both). 

The MRT Purifier, developed for Tecnimont-KT in the framework of FISR project, has been designed to house five membrane modules and operate at 450°C and up to 25 barg. Each module consists of two double sided, planar 30 cm X 12 cm membrane panels welded in series. Each panel has a palladium (Pd) alloy active membrane area of 0.03 m per side for a total installed membrane area of 0.6 m in the purifier. The modules are housed in a rectangular core which, along with the inlet distributor, promotes uniform reformate flow across the membrane modules. The core assembly (Fig. 3.11) is housed inside a pressure vessel. 

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