Progesterone receptor stimulates transcription of mouse mammary tumour virus in a cell-free system

Article Abstract:

The expression of the mouse mammary tumor virus (MMTV) is regulated by the binding of steroid hormones. When hormones bind to a receptor on the promotor, the portion of the DNA which is involved in the regulation of expression, the virus is expressed in large amounts. Using molecules of the receptor that have been mutated or changed, sites on the receptor which are involved in binding to the hormone, known as hormone response elements (HREs), and sites which are involved in the activation of the DNA for expression have been identified. A system has been devised which allows the expression of the MMTV to occur in the test tube, outside of the cell, with only the proteins and hormones necessary for expression; this is accomplished using a progesterone steroid hormone receptor from rabbit uterus. Expression of genes from the MMTV promotor is increased up to 10-fold when the progesterone receptor is added. If the MMTV DNA is deleted or mutated in the HRE region, the stimulatory effect is not seen, indicating that the high expression depends on the binding to the MMTV DNA. The activity also depends on the binding of the hormone to the receptor. This system should be useful in understanding the mechanism of gene expression which is regulated by steroid hormones. (Consumer Summary produced by Reliance Medical Information, Inc.)

Methods, Physiological aspects, Genetic transcription, Transcription (Genetics), Steroid hormones, Progesterone, Hormone research, Progesterone receptors

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Syncytin is a captive retroviral envelope protein involved in human placental morphogenesis

Article Abstract:

It has been possible to identify a captured retroviral gene, syncytin, which may be significant in human placental biology. It was established that the key sites of syncytin expression are placental syncytiotrophoblasts, multinucleated cells originating from fetal trophoblasts. Expression of recombinant syncytin in a wide range of cell types leads to the formation of giant syncytia. Preliminary observations of increased IL-12 secretion in syncytin-fused COS cells could suggest that fused cells have greater secretory abilities.

Pregnancy proteins

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Infection by procine endogenous retrovirus after islet xenotransplantation in SCID mice

Article Abstract:

Pig pancreatic islets are found to produce porcine endogenous retroviruses which can infect human cells in culture.

Usage, Animals, Islands of Langerhans, Islets of Langerhans

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