Promoter clearance

Postural drainage may assist in promoting clearance of pulmonary secretions. 

Marambaud, P., Zhao, H., Davies, P. (2005) Resveratrol promotes clearance of Alzheimer s disease amyloid- 3 peptides. J. Biol. Chem., 280, 37377-37382. 

TFIIH 9 35-89 hehcase, protein kinase and ATPase-activity promoter unwinding, promoter clearance ( )... 

The pharmacokinetics and metabolism of tazarotene (2) is especially worth noting. Topical gel application provides the direct delivery of tazarotene into the skin. Ten hours after a topical application of 0.1% tazarotene gel to the skin, approximately 4-6% of the dose resides in the stratum comeum and 2% of the dose is distributed to the viable epidermis and dermis. As depicted in Scheme 3, both tazarotene (2) and tazarotenic acid (11) undergo further metabolism to their corresponding sulfoxides 12 and 13, respectively. Sulfoxides 12 and 13, in turn, are even further oxidized to sulfones 14 and 15, respectively. These very polar metabolites do not accumulate in adipose tissue, but are rapidly eliminated via both urinary and fecal pathways with a terminal half-life of approximately 18 h. A lesson learned here is that installation of a sulfide moiety promotes clearance because it is oxidized to polar metabolites that are rapidly cleared. As the consequence, the systemic exposure is minimized. Percutaneous absorption of tazarotene (2) led to a plasma concentration below 1 gg/L. The systemic... 

RNA Strand Initiation and Promoter Clearance TFIIH has an additional function during the initiation phase. A kinase activity in one of its subunits phosphorylates Pol II at many places in the CTD (Fig. 26-9). Several other protein kinases, including CDK9 (cyclin-dependent kinase 9), which is part of the complex pTEFb (positive transcription elongation/actor b), also phosphorylate the... 

Rifampicin inhibits bacterial RNA synthesis by binding to the )3 subunit of bacterial RNA polymerases, preventing the promoter clearance step of transcription (Fig. 26-6). It is sometimes used as an antibiotic. 

Goodrich, J.A. and Tjian, R. (1994) Transcription factors HE and IIH Band ATP hydrolysis direct promoter clearance by RNA polymerase n. Cell, 77,145-156. 

Liu, C., and Martin, C. T. (2002). Promoter clearance by T7 RNA polymerase. Initial bubble collapse and transcript dissociation monitored by base analog fluorescence. J. Biol. Chem. 277, 2725-2731. 

The rate of removal of mucus from the airways is determined by such factors as mucus viscosity, the amount of mucus produced, and the degree of ciliary activity. These processes may be influenced by a variety of diseases, including asthma, cystic fibrosis, and chronic bronchitis [82,83], In patients suffering from cystic fibrosis or chronic bronchitis, mucus hypersecretion is evident and mucociliary function is impaired. The failure to clear mucus from the airways leads to airway obstruction and to chronic colonization of the airways with bacterial organisms (which leads to lung infections and airway inflammation and damage). In asthmatic subjects, airway mucus is more viscous and ciliary transport mechanisms are inhibited [82,83]. In these diseases, the therapeutic objective is to improve mucus clearance from the airways. For example, aerosols of water or saline (especially hypertonic saline) promote clearance of mucus by... 

Viswanathan, A. and Doetsch, P.W. (1998) Effects of nonbulky DNA base damages on Escherichia coli RNA polymerase-mediated elongation and promoter clearance. J. Biol. Chem., 2Ti, 21276-21281. 

Promoter melting using helicase activity promoter clearance ( ) by CTD kinase activity... 

TFIIH 9 525 total Promoter melting promoter clearance via phosphorylation ofCTD... 

Its primary function is as a general transcription factor involved in the formation of the open complex for transcription initiation. It binds to the basal unit and is involved in DNA melting through a helicase activity as well as promoter clearance via phosphorylation of the CTD of RNA polymerase. In addition, it also has a cyclin-dependent kinase activity. Thus, TFIIH is involved in tying transcription and cell division together. It is also involved in DNA repair mechanisms. 

Transitions that underlie promoter clearance may be rationalized with the Pol II structures. At the very beginning of transcription, contacts of Pol II with nascent RNA are crucial. To allow for the synthesis of the first phosphodiester bond, nucleoside triphosphates must be held by the protein. The resulting dinucleotide RNA must still be held by protein— RNA contacts, as observed in the core elongation complex structure (Gnatt et al., 2001), as the energy of base-pairing alone is insufficient for its retention. Equally, RNA is still bound by Pol II at the position of the third nucleotide. Despite the observed RNA-Pol II contacts, short RNA... 

After successful promoter clearance, the early elongation complex can pause in a promoter proximal position (Albert et al., 1997 Li et al., 1996 Raschke et al., 1999). This promoter-proximal pausing of polymerase... 

Maxon, M. E., Goodrich, J. A., and Tjian, R. (1994). Transcription factor HE binds preferentially to RNA polymerase IIA and recruits TFIIH a model for promoter clearance. Genes Dev. 8, 515-524. 

New evidence reveals a role for HATs in additional cellular processes beyond transcriptional intiation. HAT activity in transcriptional elongation likely facilitates RNAPII during promoter clearance and transcription through coding regions. Also, data indicate that HATs play an active role in DNA repair, revealing that modifiers may play an important part in any chromatin-templated process. 

TFIIH 35-89 9 Promoter melting using helicase activity, promoter clearance via CTD phosphorylation... 

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