scholarly journals Transcription factor access is mediated by accurately positioned nucleosomes on the mouse mammary tumor virus promoter.

1991 ◽  
Vol 11 (2) ◽  
pp. 688-698 ◽  
Author(s):  
T K Archer ◽  
M G Cordingley ◽  
R G Wolford ◽  
G L Hager
Keyword(s):  
Mammary Tumor ◽  
Transcription Initiation ◽  
Mouse Mammary Tumor Virus ◽  
Initiation Complex ◽  
Mammary Tumor Virus ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Nuclear Factor 1

A fragment of the mouse mammary tumor virus (MMTV) promoter was reconstituted from pure histones into a dinucleosome with uniquely positioned octamer cores. Core boundaries for the in vitro-assembled dinucleosome corresponded to the observed in vivo phasing pattern for long terminal repeat nucleosomes A and B. Nuclear factor 1 (NF1), a constituent of the MMTV transcription initiation complex, was excluded from the assembled dinucleosome, whereas the glucocorticoid receptor was able to bind. During transcription of MMTV in vivo, displacement of nucleosome B was necessary to permit assembly of the initiation complex. These results indicate that the nucleoprotein structure of the promoter can provide differential access to sequence-specific DNA-binding proteins and that active chromatin remodeling can occur during transcription activation.

Transcription factor access is mediated by accurately positioned nucleosomes on the mouse mammary tumor virus promoter

1991 ◽  
Vol 11 (2) ◽  
pp. 688-698
Author(s):  
T K Archer ◽  
M G Cordingley ◽  
R G Wolford ◽  
G L Hager
Keyword(s):  
Mammary Tumor ◽  
Transcription Initiation ◽  
Mouse Mammary Tumor Virus ◽  
Initiation Complex ◽  
Mammary Tumor Virus ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Nuclear Factor 1

A fragment of the mouse mammary tumor virus (MMTV) promoter was reconstituted from pure histones into a dinucleosome with uniquely positioned octamer cores. Core boundaries for the in vitro-assembled dinucleosome corresponded to the observed in vivo phasing pattern for long terminal repeat nucleosomes A and B. Nuclear factor 1 (NF1), a constituent of the MMTV transcription initiation complex, was excluded from the assembled dinucleosome, whereas the glucocorticoid receptor was able to bind. During transcription of MMTV in vivo, displacement of nucleosome B was necessary to permit assembly of the initiation complex. These results indicate that the nucleoprotein structure of the promoter can provide differential access to sequence-specific DNA-binding proteins and that active chromatin remodeling can occur during transcription activation.

scholarly journals Nucleosome-mediated disruption of transcription factor-chromatin initiation complexes at the mouse mammary tumor virus long terminal repeat in vivo.

1994 ◽  
Vol 14 (1) ◽  
pp. 32-41 ◽  
Author(s):  
H L Lee ◽  
T K Archer
Keyword(s):  
Mammary Tumor ◽  
Dna Sequences ◽  
Mouse Mammary Tumor Virus ◽  
Binding Protein ◽  
Tata Binding Protein ◽  
Mammary Tumor Virus ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Nuclear Factor 1

Glucocorticoid induction of mouse mammary tumor virus (MMTV) is short lived, returning to base levels within 24 h despite the continued presence of hormone. MMTV DNA sequences assembled as chromatin require hormone for binding by nuclear factor 1 (NF1) and octamer proteins (OCT). However, in the same cells, NF1 and OCT factors are bound to transiently introduced DNA in the absence of hormone. In contrast, recruitment of the TATA-binding protein and a novel DNA-binding protein, which we have designated FDT, for factor downstream of the TATA-binding protein, is hormone dependent for both stable and transient templates. Furthermore, transient DNA templates, but not nucleosomal templates, retain these transcription factors over the course of 24 h. This finding suggests that MMTV chromatin structure contributes to activation and cessation of transcription in vivo.

scholarly journals Mouse Mammary Tumor Virus Promoter-Containing Retroviral Promoter Conversion Vectors for Gene-Directed Enzyme Prodrug Therapy are Functional in Vitro and in Vivo

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
Reinhard Klein ◽  
Bärbel Ruttkowski ◽  
Sonja Schwab ◽  
Thomas Peterbauer ◽  
Brian Salmons ◽  
...  
Keyword(s):  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Viral Vector ◽  
Transgenic Animals ◽  
Mammary Tumor Virus ◽  
Enzyme Prodrug Therapy ◽  
Mouse Mammary Tumor ◽  
Tumor Virus

Gene directed-enzyme prodrug therapy (GDEPT) is an approach for sensitization of tumor cells to an enzymatically activated, otherwise nontoxic, prodrug. Cytochrome P450 2B1 (CYP2B1) metabolizes the prodrugs cyclophosphamide (CPA) and ifosfamide (IFA) to produce the cytotoxic substances phosphoramide mustard and isophosphoramide mustard as well as the byproduct acrolein. We have constructed a retroviral promoter conversion (ProCon) vector for breast cancer GDEPT. The vector allows expression of CYP2B1 from the mouse mammary tumor virus (MMTV) promoter known to be active in the mammary glands of transgenic animals. It is anticipated to be used for the generation of encapsulated viral vector producing cells which, when placed inside or close to a tumor, will act as suppliers of the therapeutic CYP2B1 protein as well as of the therapeutic vector itself. The generated vector was effectively packaged by virus producing cells and allowed the production of high levels of enzymatically active CYP2B1 in infected cells which sensitized them to killing upon treatment with both IFA and CPA. Determination of the respectiveIC50values demonstrated that the effective IFA dose was reduced by sixteen folds. Infection efficiencies in vivo were determined using a reporter gene-bearing vector in a mammary cancer cell-derived xenograft tumor mouse model.

scholarly journals Nucleosome-mediated disruption of transcription factor-chromatin initiation complexes at the mouse mammary tumor virus long terminal repeat in vivo

1994 ◽  
Vol 14 (1) ◽  
pp. 32-41
Author(s):  
H L Lee ◽  
T K Archer
Keyword(s):  
Mammary Tumor ◽  
Dna Sequences ◽  
Mouse Mammary Tumor Virus ◽  
Binding Protein ◽  
Tata Binding Protein ◽  
Mammary Tumor Virus ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Nuclear Factor 1

Glucocorticoid induction of mouse mammary tumor virus (MMTV) is short lived, returning to base levels within 24 h despite the continued presence of hormone. MMTV DNA sequences assembled as chromatin require hormone for binding by nuclear factor 1 (NF1) and octamer proteins (OCT). However, in the same cells, NF1 and OCT factors are bound to transiently introduced DNA in the absence of hormone. In contrast, recruitment of the TATA-binding protein and a novel DNA-binding protein, which we have designated FDT, for factor downstream of the TATA-binding protein, is hormone dependent for both stable and transient templates. Furthermore, transient DNA templates, but not nucleosomal templates, retain these transcription factors over the course of 24 h. This finding suggests that MMTV chromatin structure contributes to activation and cessation of transcription in vivo.

scholarly journals Expression of Mouse Mammary Tumor Virus Envelope Protein Does Not Prevent Superinfection In Vivo or In Vitro

Virology ◽  
1999 ◽  
Vol 263 (2) ◽  
pp. 418-426 ◽  
Author(s):  
John L. Dzuris ◽  
Wei Zhu ◽  
Denis Kapkov ◽  
Tatyana V. Golovkina ◽  
Susan R. Ross
Keyword(s):  
Mammary Tumor ◽  
Envelope Protein ◽  
Mouse Mammary Tumor Virus ◽  
Virus Envelope ◽  
Mammary Tumor Virus ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Virus Envelope Protein

scholarly journals Heregulin Co-opts PR Transcriptional Action Via Stat3 Role As a Coregulator to Drive Cancer Growth

2015 ◽  
Vol 29 (10) ◽  
pp. 1468-1485 ◽  
Author(s):  
Cecilia J. Proietti ◽  
Franco Izzo ◽  
María Celeste Díaz Flaqué ◽  
Rosalía Cordo Russo ◽  
Leandro Venturutti ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Signaling Pathways ◽  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Cancer Growth ◽  
Mammary Tumor Virus ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Virus Promoter

Abstract Accumulated findings have demonstrated the presence of bidirectional interactions between progesterone receptor (PR) and the ErbB family of receptor tyrosine kinases signaling pathways in breast cancer. We previously revealed signal transducer and activator of transcription 3 (Stat3) as a nodal convergence point between said signaling pathways proving that Stat3 is activated by one of the ErbBs' ligands, heregulin (HRG)β1 via ErbB2 and through the co-option of PR as a signaling molecule. Here, we found that HRGβ1 induced Stat3 recruitment to the promoters of the progestin-regulated cell cycle modulators Bcl-XL and p21CIP1 and also stimulated Stat3 binding to the mouse mammary tumor virus promoter, which carries consensus progesterone response elements. Interestingly, HRGβ1-activated Stat3 displayed differential functions on PR activity depending on the promoter bound. Indeed, Stat3 was required for PR binding in bcl-X, p21CIP1, and c-myc promoters while exerting a PR coactivator function on the mouse mammary tumor virus promoter. Stat3 also proved to be necessary for HRGβ1-induced in vivo tumor growth. Our results endow Stat3 a novel function as a coregulator of HRGβ1-activated PR to promote breast cancer growth. These findings underscore the importance of understanding the complex interactions between PR and other regulatory factors, such as Stat3, that contribute to determine the context-dependent transcriptional actions of PR.

scholarly journals Bone marrow stromal cell antigen 2 (BST-2) restricts mouse mammary tumor virus (MMTV) replication in vivo

Retrovirology ◽  
2012 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Philip H Jones ◽  
Harshini V Mehta ◽  
Martina Maric ◽  
Richard J Roller ◽  
Chioma M Okeoma
Keyword(s):  
Bone Marrow ◽  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Stromal Cell ◽  
Bone Marrow Stromal Cell ◽  
Mammary Tumor Virus ◽  
Marrow Stromal Cell ◽  
Mouse Mammary Tumor ◽  
Tumor Virus
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