Covert infection of a mouse mammary tumor cell line withMycoplasma hyorhinis: Cosedimentation with mouse mammary tumor virus in sucrose density gradients

In Vitro ◽  
1981 ◽  
Vol 17 (11) ◽  
pp. 997-1003 ◽  
Author(s):  
Robert J. Sydiskis ◽  
Patricia A. Weber ◽  
Richard A. Giudice
Keyword(s):  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Tumor Cell Line ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cell Line ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Mouse Mammary Tumor Cell ◽  
Covert Infection

scholarly journals Mutations in the hormone regulatory element of mouse mammary tumor virus differentially affect the response to progestins, androgens, and glucocorticoids.

1989 ◽  
Vol 9 (9) ◽  
pp. 3999-4008 ◽  
Author(s):  
P L Gowland ◽  
E Buetti
Keyword(s):  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Regulatory Element ◽  
Tumor Cell Line ◽  
Proximal Region ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cell Line ◽  
Mouse Mammary Tumor ◽  
Tumor Virus

Transcription of the mouse mammary tumor virus DNA is known to be induced by several steroid hormones. Using chimeric MMTV plasmids containing mutations within the hormone regulatory element, we have previously studied the regions required for the glucocorticoid response in mouse fibroblasts. Here we report the characterization of elements essential for the stimulation by progestins and androgens as compared with glucocorticoids. The same set of mutant plasmids was transfected into the human mammary tumor cell line T47D, and the specific transcripts were analyzed by an S1 nuclease protection assay. Androgen-mediated stimulation, although weak, showed an extended sensitivity to mutations, with a slight preference for the proximal region. The results with progestin suggest that sequences within all the described sites protected by the receptor in vitro are required and that the promoter-proximal region (-128 to -78 from the RNA start site) is more important than the distal one (-190 to -160). Moreover, a binding site for nuclear factor I was not required for the progestin response, whereas it was required for glucocorticoids. Thus, the various steroid receptors play a role in the differential regulation of mouse mammary tumor virus transcription by recognizing distinct sequence differences in the hormone regulatory element and interacting with different factors bound to the promoter.

scholarly journals Mutations in the hormone regulatory element of mouse mammary tumor virus differentially affect the response to progestins, androgens, and glucocorticoids

1989 ◽  
Vol 9 (9) ◽  
pp. 3999-4008
Author(s):  
P L Gowland ◽  
E Buetti
Keyword(s):  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Regulatory Element ◽  
Tumor Cell Line ◽  
Proximal Region ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cell Line ◽  
Mouse Mammary Tumor ◽  
Tumor Virus

Transcription of the mouse mammary tumor virus DNA is known to be induced by several steroid hormones. Using chimeric MMTV plasmids containing mutations within the hormone regulatory element, we have previously studied the regions required for the glucocorticoid response in mouse fibroblasts. Here we report the characterization of elements essential for the stimulation by progestins and androgens as compared with glucocorticoids. The same set of mutant plasmids was transfected into the human mammary tumor cell line T47D, and the specific transcripts were analyzed by an S1 nuclease protection assay. Androgen-mediated stimulation, although weak, showed an extended sensitivity to mutations, with a slight preference for the proximal region. The results with progestin suggest that sequences within all the described sites protected by the receptor in vitro are required and that the promoter-proximal region (-128 to -78 from the RNA start site) is more important than the distal one (-190 to -160). Moreover, a binding site for nuclear factor I was not required for the progestin response, whereas it was required for glucocorticoids. Thus, the various steroid receptors play a role in the differential regulation of mouse mammary tumor virus transcription by recognizing distinct sequence differences in the hormone regulatory element and interacting with different factors bound to the promoter.

Androgen regulation by the long terminal repeat of mouse mammary tumor virus

1986 ◽  
Vol 6 (8) ◽  
pp. 2847-2854
Author(s):  
P Darbre ◽  
M Page ◽  
R J King
Keyword(s):  
Long Terminal Repeat ◽  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Terminal Repeat ◽  
Regulatory Sequences ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cell Line ◽  
Mouse Mammary Tumor ◽  
Tumor Virus

Mouse mammary tumor virus (MMTV) has long been implicated in mouse mammary carcinogenesis, and it is now well established that the long terminal repeat (LTR) contains regulatory sequences responsible for glucocorticoid-mediated induction of viral RNA. However, we have demonstrated previously that androgens as well as glucocorticoids can regulate MMTV RNA in the S115 mouse mammary tumor cell line. To determine if androgens act directly on the LTR in these cells, plasmids were constructed with the MMTV LTR joined to the coding sequences of genes not normally expressed in the cells. Following transfection of these chimeric genes into S115 cells, we show that the expression of the genes is regulated by both androgens and glucocorticoids. Furthermore, hormonal regulation is also conferred by the LTR on the neighboring guanine phosphoribosyltransferase (gpt) gene. Thus, androgens can act on the LTR of MMTV when the appropriate receptors are present in the cells, and this interaction can influence the expression of additional adjacent genes.

scholarly journals Androgen regulation by the long terminal repeat of mouse mammary tumor virus.

1986 ◽  
Vol 6 (8) ◽  
pp. 2847-2854 ◽  
Author(s):  
P Darbre ◽  
M Page ◽  
R J King
Keyword(s):  
Long Terminal Repeat ◽  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Terminal Repeat ◽  
Regulatory Sequences ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cell Line ◽  
Mouse Mammary Tumor ◽  
Tumor Virus

Mouse mammary tumor virus (MMTV) has long been implicated in mouse mammary carcinogenesis, and it is now well established that the long terminal repeat (LTR) contains regulatory sequences responsible for glucocorticoid-mediated induction of viral RNA. However, we have demonstrated previously that androgens as well as glucocorticoids can regulate MMTV RNA in the S115 mouse mammary tumor cell line. To determine if androgens act directly on the LTR in these cells, plasmids were constructed with the MMTV LTR joined to the coding sequences of genes not normally expressed in the cells. Following transfection of these chimeric genes into S115 cells, we show that the expression of the genes is regulated by both androgens and glucocorticoids. Furthermore, hormonal regulation is also conferred by the LTR on the neighboring guanine phosphoribosyltransferase (gpt) gene. Thus, androgens can act on the LTR of MMTV when the appropriate receptors are present in the cells, and this interaction can influence the expression of additional adjacent genes.

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