Enhancer sequences

Subsequently, biological/physical treatment of leachate with an activated carbon-enhanced sequencing batch bioreactor (PAC-SBR) was analyzed to determine whether the improved treatment by simultaneous adsorption and biodegradation in the SBR would produce an acceptable effluent without post-treatment in the existing granular activated carbon adsorber (Ying et al., 1986). 

Ying, W.C., R.R. Bonk and S.A. Sojka. Treatment of Landfill Leachate in Powered Activated Carbon Enhanced Sequencing Batch Bioreactors. In Proc. of the 18th Mid-Atlantic Ind. Waste Conference, Technomic Publishing Company, Inc., Lancaster, Pennsylvania, 1986. 

Fig. 7. The use of stress-inducible promoter and enhancer sequences. STRESS-INDUCIBLE PROMOTER /ENHANCER...

Carotenoids have been found to exert numerous other effects of potential importance for the RPE. Carotenoids can activate transcription pathways (Ben-Dor et al., 2005 Kalariya et al., 2008 Palozza et al., 2006 Sharoni et al., 2004) for example, by activation of the antioxidant response element (ARE) (Ben-Dor et al., 2005 Sharoni et al., 2004). The ARE is an enhancer sequence responsible for the expression of many phase-II detoxification and antioxidant genes. Thus carotenoids may upregulate cellular antioxidant defenses. 

Positive regulators (enhancers) Turn on transcription when a specific effector protein binds to a specific enhancer sequence in the DNA. 

The orientation of the enhancer sequence with respect to the gene is not important. 

Fig. 1. Pulse sequences for determining spin-lattice relaxation time constants. Thin bars represent tt/2 pulses and thick bars represent tt pulses, (a) The inversion-recovery sequence, (b) the INEPT-enhanced inversion recovery, (c) a two-dimensional proton-detected INEPT-enhanced sequence and (d) the CREPE sequence. T is the waiting period between individual scans. In (b) and (c), A is set to (1 /4) Jm and A is set to (1 /4) Jm to maximize the intensity of IH heteronuclei and to (1/8) Jm to maximize the intensity of IH2 spins. The phase cycling in (c) is as follows 4>i = 8(j/),8(-j/) 3 = -y,y A = 2(x),2(-x) Acq = X, 2 —x), X, —X, 2(x), —x, —x, 2(x), —x, x, 2 —x),x. The one-dimensional version of the proton-detected experiment can be obtained by omitting the f delay. In sequence (d), the phase 4> is chosen as increments of 27r/16 in a series of 16 experiments.

Alternative mRNA splicing detection and analysis of human exonic enhancer sequences using genomic SELEX... 

Sen, R. and Baltimore, D. (1986). Multiple nuclear factors interact with the immunoglobulin enhancer sequences. Cell 46, 705-715. 

Up to 2000 base pairs separate the enhancer sequence from the gene it regulates. 

An enhancer sequence can be "downstream1 from the promoter region. 

Enhancer-binding transcription factors bound to enhancer sequences at sites far from the gene... 

NtrC-P dimerizes and binds to the enhancer sequence, where it appears to catalyze an ATP-depen-dent isomerization of the closed to open forms of the transcription initiation complex (Eq. 28-1).153/154 The isomerization may depend upon looping.152 Other operons that utilize the oN subunit of RNAP often also have upstream or downstream enhancers.155156... 

The presence of an enhancer sequence may cause as much as 100- to 1000-fold increase in the rate of transcription as compared with the same transcriptional emit from which the enhancer has been deleted. A surprising fact is that enhancers as far as 1 -2 kbp upstream or even far downstream of the promoter and in either of the two possible orientations are effective. range conformational alterations in DNA. Alternatively, they might contain points of entry for RNA polymerase or for an initiation factor that could move along the DNA to the promoter region. However, the synthetic DNA molecule shown in Fig. 28-14 contains two copies of an enhancer in opposite orientations in one strand but none in the other strand.354 The... 

Figure 28-14 A "tailed circle" consisting of an enhancer linked to, but topologically separated from, a gene. One of the DNA strands of this plasmid bears two copies of an SV40 enhancer sequence, one copy inverted with respect to the other. This extra region protrudes from the circle and self-pairs to form a functional enhancer. The main body of the circle contains the p-globin gene, transcription of which is increased by the enhancer. Twisting of the enhancer has no effect on the winding of the strands on the main body of the circle nevertheless, the enhancer efficiently increases P-globin transcription. From Ptashne.355...

How can a DNA enhancer sequence located as many as several thousand base pairs from a gene transcription start site influence transcription even if its orientation is reversed ... 

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