Protein transcripts

The viral protein Rev may also play a role in HIV-1 latency. Expression of the viral Rev protein is essential for the nuclear export of genomic RNA as well as unspliced and/or singly spliced transcripts (Cullen 2003), which are ultimately translated into structural, regulatory, and enzymatic viral proteins. Retention of Rev and Tat (viral transactivator proteins) transcripts in the nucleus of resting CD4h- T cells from HAART patients (Lassen et al. 2006) might be involved in the maintenance of post-integration latency in these cells. Importantly, this phenomenon is non-existent in activated T cells. 

Rogers, J.T., Randall, J.D., Cahill, C.M., Eder, P.S., et al. (2002) An iron-responsive element type II in the 5 -untranslated region of the Alzheimer s amyloid precursor protein transcript, J. Biol. Chem., 277, 45518-45528. 

Chintharlapalli S, Papineni S, Ramaiah SK, Safe S. (2(X)7) Betuhnic acid inhibits prostate cancer growth through inhibition of specificity protein transcription factors. Cancer Res 67 2816-2823. 

Regulatory proteins (transcription factors) are involved in controlling gene expression in all cells. These regulatory proteins bind to specific DNA sequences and thereby activate or inhibit the transcription of genes (Transcription control). The effects of transcription factors are usually reversible and are often controlled by ligands or by interconversion. 

The nucleus is not capable of synthesizing proteins. All of the nuclear proteins therefore have to be imported—the histones with which DNA is associated in chromatin, and also the so-called non-histone proteins (DNA polymerases and RNA polymerases, auxiliary and structural proteins, transcription factors, and ribosomal proteins). Ribosomal RNA (rRNA) already associates with proteins in the nucleolus to form ribosome precursors. 

Kosa, P. E, Ghosh, G., DeDecker, B. S. and Sigler, P. B. (1997). The 2.1-A crystal structure of an archaeal preinitiation complex TATA-box-binding protein/transcription factor (II)B core/TATA-box. Proc. Nat. Acad. Sci. USA 94, 6042-6047. 

In contrast to the repression by REV-ERB proteins, transcriptional activation by members of the ROR orphan receptors may require only a single RORE (Sundvold Lien 2001, Zamir et al 1997). We thus propose that the competitive binding of ROR and REV-ERB members to RORE elements accounts for the cyclic transcription of Bmal1 (Fig. 2). RORxoactivator complexes fill the two RORE elements at times when REV-ERB proteins are present at nadir levels, but are displaced by the cooperatively binding [REV-ERB]2 NcoRl complexes... 

Miller, J. (1985) Repetitive zinc-binding domains in the protein transcription factor IIIA from Xenopus oocytes. EMBO J 4 1609-1614. 

The technique has been used for the total synthesis of truncated forms of the basic/helix-loop-helix/zipper domains of the nuclear protein transcription regulation factors cMyc and Max. These were covalently joined through an oxime bond to form a single protein-like entity with two amino termini, i.e. cMyc-Max heterodimer and Max-Max homodimer, each 172 residues, which bind to DNA and activate or inhibit mRNA transcription. 103 ... 

A further possibility for indirect repression results from heterodimerization (see 1.4.4.3). Heterodimers between two transcription factors, in which one of the partners possesses a DNA-binding domain with weak affinity, can inactivate a transcriptional activator in a heterodimer complex. Since a strong binding to the DNA element usually requires both subimits of a DNA-binding protein, transcription activation by this type of heterodimer is not possible. 

Binding of protein transcription factors and RNA polymerase to promoter sites at the beginning of I a gene... 

The cell cycle encompasses so many different processes that it is clearly impossible to describe it by the single diagram of Fig. 11-15 or by the text written here. The cycle is influenced by a host of growth factors and external stimuli, many of which act on transcription of cyclins and other essential proteins. Transcription factors such as those of the Fos / Jim (AP-1) family in response to the MAP cascade (Fig. 11-13) are among those that control the transcription of cyclins.262 263c However, during mitosis most transcription of any genes is repressed 264... 

Several of the protein transcription factors of archaea also resemble those of eukaryotes.267 268 However, in a comparison of DNA sequences from the complete genomes of four archaeal species, it was found that of 280 predicted transcription factors or transcription-associated proteins 168 were homologous to bacterial proteins and only 51 to eukaryotic proteins.268 This tends to confirm the ancient divergence of the three primary domains of life. 

These are but two of the types of domains found to be involved in transcription activation. Undoubtedly, this list will grow in the near future, as will our understanding about how these transcription activation domains work. Thus far they are likely to represent regions that function by contacting other regulatory proteins, transcription factors, and the RNA polymerase itself. 

Reverse transcriptase Hypothetical protein Ubiquitin Soma ferritin Cytochrome p450 NADH dehydrogenase Ribosomal proteins Transcription initation protein T ransposase Primosomal protein N ... 

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