scholarly journals Transcription Properties of a Cell Type–Specific TATA-Binding Protein, TRF

Cell ◽  
1997 ◽  
Vol 91 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Stig K Hansen ◽  
Shinako Takada ◽  
Raymond H Jacobson ◽  
John T Lis ◽  
Robert Tjian
1993 ◽  
Vol 13 (5) ◽  
pp. 3103-3112
Author(s):  
S Haas ◽  
J Gordon ◽  
K Khalili

Transcription of the myelin basic protein (MBP) gene is regulated in a cell-type-specific and developmental stage-specific manner during myelin formation in the murine central nervous system. The 5'-flanking region of the MBP gene contains several regulatory elements that differentially contribute to the cell-type-specific transcription of MBP in cells derived from the central nervous system. The proximal element, termed MB1, which is located between nucleotides -14 and -50 with respect to the RNA start site, has previously been shown to have characteristics of a cell-type-specific enhancer element. In this study, we used band shift and UV cross-linking assays to identify DNA-binding proteins in mouse brain nuclear extract which interact with the MB1 element. Fractionation of these extracts has allowed the identification of a 38- to 41-kDa nuclear protein, derived from mouse brain tissue at the peak of myelination, which specifically binds the MB1 DNA sequence. Fractions enriched in the MB1-binding protein have been shown to stimulate transcription of the MBP promoter in extract derived from HeLa cells. MB1 binding protein activity is expressed in a tissue-specific and development stage-specific pattern which coincides with the pattern of MBP transcription, suggesting that this protein may be a biologically relevant transcription factor for the MBP gene in vivo.


1993 ◽  
Vol 13 (5) ◽  
pp. 3103-3112 ◽  
Author(s):  
S Haas ◽  
J Gordon ◽  
K Khalili

Transcription of the myelin basic protein (MBP) gene is regulated in a cell-type-specific and developmental stage-specific manner during myelin formation in the murine central nervous system. The 5'-flanking region of the MBP gene contains several regulatory elements that differentially contribute to the cell-type-specific transcription of MBP in cells derived from the central nervous system. The proximal element, termed MB1, which is located between nucleotides -14 and -50 with respect to the RNA start site, has previously been shown to have characteristics of a cell-type-specific enhancer element. In this study, we used band shift and UV cross-linking assays to identify DNA-binding proteins in mouse brain nuclear extract which interact with the MB1 element. Fractionation of these extracts has allowed the identification of a 38- to 41-kDa nuclear protein, derived from mouse brain tissue at the peak of myelination, which specifically binds the MB1 DNA sequence. Fractions enriched in the MB1-binding protein have been shown to stimulate transcription of the MBP promoter in extract derived from HeLa cells. MB1 binding protein activity is expressed in a tissue-specific and development stage-specific pattern which coincides with the pattern of MBP transcription, suggesting that this protein may be a biologically relevant transcription factor for the MBP gene in vivo.


1998 ◽  
Vol 72 (3) ◽  
pp. 2113-2124 ◽  
Author(s):  
Tobias Bauknecht ◽  
Yang Shi

ABSTRACT The human papillomavirus type 18 (HPV-18) upstream regulatory region (URR) controls cell type-specific expression of viral oncoproteins E6 and E7. The HPV-18 URR is highly active in HeLa cells, but its activity is virtually undetectable in HepG2 cells. Previous work has shown that YY1 plays an important role in activation of the HPV-18 URR in HeLa cells, and this activating activity is dependent on its physical interaction with C/EBPβ, which binds to the switch region adjacent to the YY1 site in the URR. Overexpression of C/EBPβ in HepG2 cells restores C/EBPβ-YY1 interaction, resulting in strong activation of the HPV-18 URR activity. In this report, we show that, in contrast to the effect in HepG2 cells, overexpression of C/EBPβ represses the HPV-18 URR in HeLa cells. This C/EBPβ-induced repression of the HPV-18 URR in HeLa cells is binding site independent. It is also promoter specific, since it activates the albumin promoter under conditions in which it represses the URR in the same cells. Biochemical analysis shows that overexpression of C/EBPβ in HeLa cells specifically interferes with binding of TATA-binding protein to the TATA box of the HPV-18 URR, but its overexpression in HepG2 cells leads to activation of the HPV-18 URR. These results suggest that a molecular mechanism underlies the ability of C/EBPβ to regulate transcription in a cell type-specific manner and indicate the potential of using C/EBPβ to manipulate the activity of the HPV-18 URR in cervical carcinoma cells.


2017 ◽  
Vol 55 (05) ◽  
pp. e28-e56
Author(s):  
S Macheiner ◽  
R Gerner ◽  
A Pfister ◽  
A Moschen ◽  
H Tilg

2020 ◽  
Vol 528 (13) ◽  
pp. 2218-2238 ◽  
Author(s):  
Attilio Iemolo ◽  
Patricia Montilla‐Perez ◽  
I‐Chi Lai ◽  
Yinuo Meng ◽  
Syreeta Nolan ◽  
...  

2021 ◽  
Author(s):  
Moataz Dowaidar

Autophagy is a double-edged sword in cancer, and numerous aspects should be taken into account before deciding on the most effective strategy to target the process. The fact that several clinical studies are now ongoing does not mean that the patient group that may benefit from autophagy-targeting medicines has been identified. Autophagy inhibitors that are more potent and specialized, as well as autophagy indicators, are also desperately required. The fact that these inhibitors only work against tumors that rely on autophagy for survival (RAS mutants) makes it difficult to distinguish them from tumors that continue to develop even when autophagy is absent. Furthermore, mutations such as BRAF have been shown to make tumors more susceptible to autophagy suppression, suggesting that targeting such tumours may be a viable strategy for overcoming their chemotherapy resistance. In the meantime, we are unable to identify if autophagy regulation works in vivo or whether it selectively targets a disease while inflicting injury to other healthy organs and tissues. A cell-type-specific impact appears to be observed with such therapy. As a result, it is just as important to consider the differences between tumors that originate in different organs as it is to consider the signaling pathways that are similar across them. For a therapy or cure to be effective, the proposed intervention must be tailored to the specific needs of each patient.Over the last several years, a growing amount of data has implicated autophagy in a variety of disorders, including cancer. In normal cells, this catabolic process is also required for cell survival and homeostasis. Despite the fact that medications targeting intermediates in the autophagy signaling pathway are being created and evaluated at both the preclinical and clinical levels, given the complicated function of autophagy in cancer, we still have a long way to go in terms of establishing an effective therapeutic approach. This article discusses current tactics for exploiting cancer cells' autophagy dependency, as well as obstacles in the area. We believe that the unanswered concerns raised in this work will stimulate researchers to investigate previously unknown connections between autophagy and other signaling pathways, which might lead to the development of novel, highly specialized autophagy therapies.


1993 ◽  
Vol 13 (9) ◽  
pp. 5301-5314 ◽  
Author(s):  
G S Huh ◽  
R O Hynes

We have investigated the regulation of splicing of one of the alternatively spliced exons in the rat fibronectin gene, the EIIIB exon. This 273-nucleotide exon is excluded by some cells and included to various degrees by others. We find that EIIIB is intrinsically poorly spliced and that both its exon sequences and its splice sites contribute to its poor recognition. Therefore, cells which recognize the EIIIB exon must have mechanisms for improving its splicing. Furthermore, in order for EIIB to be regulated, a balance must exist between the EIIIB splice sites and those of its flanking exons. Although the intron upstream of EIIIB does not appear to play a role in the recognition of EIIIB for splicing, the intron downstream contains sequence elements which can promote EIIIB recognition in a cell-type-specific fashion. These elements are located an unusually long distance from the exon that they regulate, more than 518 nucleotides downstream from EIIIB, and may represent a novel mode of exon regulation.


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