A region upstream from the mouse c-mos proto-oncogene, termed upstream mouse sequence (UMS), prevents expression of mos transforming activity. Previous studies suggested that the UMS prevented transcription readthrough. In this study, we constructed a recombinant DNA clone, pHTS3MS, with the UMS inserted downstream from both the mos gene and a truncated long terminal repeat containing only the U3 enhancer region. In this position UMS did not inhibit mos transforming activity. We examined cells transformed by pHTS3MS for RNA expression. S1 nuclease analysis showed that the UMS provides two polyadenylation signals to mos-containing RNA and nuclear run-on transcription showed that the primary transcripts terminate in UMS. In addition, using portions of the UMS, we found that a 360-bp fragment containing the UMS polyadenylation signals and sites inserted between the herpes simplex virus type 1 (HSV-1) thymidine kinase gene (tk) and its promoter inhibits tk transforming activity by 99% and prevents detectable expression of this construct in transient expression assays. Thus, the UMS must contain signals for polyadenylation and appears to function as a transcription terminator.

Although the molecularly cloned mouse c-mos oncogene locus can be efficiently activated by insertion of a retroviral long terminal repeat (LTR) 5' to its coding region, only low-frequency transformation occurs with the LTR element inserted 3' to this region. Analysis of several of the latter transformed cell lines suggested that loss of 2 kilobases (kb) of normal mouse DNA sequences preceding c-mos was required for oncogene activation. The determination of the transforming potential of deletion mutants containing only portions of this region followed by analysis of their nucleotide sequences identified a region termed upstream mouse sequence (UMS) as a cis-acting locus that prevents c-mos activation by a 3' LTR. The UMS region is approximately 1 kb in length and is located 0.8-1.8 kb upstream from the first ATG in the open reading frame of c-mos. Insertion of UMS 5' to the v-mos coding region also prevents 3' LTR enhancement of its transforming activity, but this inhibition is position dependent and functions only when inserted between v-mos and its putative promoter. The results presented here suggest that UMS may function to regulate c-mos proto-oncogene expression and may explain the lack of detectable c-mos transcripts in normal mouse cells.

Transforming growth factor alpha (TGF alpha) is one growth factor that has been circumstantially implicated in regulating the autocrine growth of breast cancer cells. Expression of TGF alpha can be modulated by activated cellular protooncogenes such as ras and by estrogens. For example, the epidermal growth factor (EGF)-responsive normal NOG-8 mouse and human MCF-10A mammary epithelial cell lines can be transformed with either a point-mutated c-Ha-ras protooncogene or with a normal or point-mutated c-neu (erbB-2) protooncogene. In ras transformed NOG-8 and MCF-10A cells but not in neu transformed cells there is a loss in or an attenuated response to the mitogenic effects of EGF. This response may be due in part to an enhanced production of endogenous TGF alpha that is coordinately and temporally linked to the expression of the activated ras gene and to the acquisition of transformation-associated properties in these cells. TGF alpha mRNA and TGF alpha protein can also be detected in approximately 50-70% of primary human breast tumors. In addition, approximately 2- to 3-fold higher levels of biologically active and immunoreactive TGF alpha can also be detected in the pleural effusions from breast cancer patients as compared with the TGF alpha levels in the serous effusions of noncancer patients. Over-expression of a full-length TGF alpha cDNA in NOG-8 and MCF-10A cells is capable of transforming these cells. Finally, expression of TGF alpha mRNA and production of biologically active TGF alpha protein is also found in normal rodent and human mammary epithelial cells.

To determine whether cyclooxygenase products mediated the attenuation of hypoxic pulmonary vasoconstriction induced by estradiol, we measured pulmonary arterial pressure at a flow of 50 ml X min-1 X kg-1 (Ppa50) during steady-state exposures to inspired O2 tensions (PIO2) between 0 and 200 Torr in isolated lungs of juvenile ewes. Intramuscular estradiol (10 mg) 44-60 h before study significantly decreased perfusate concentrations of 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), the stable metabolite of the pulmonary vasodilator, prostacyclin, but did not significantly affect the stimulus-response relationship between PIO2 and Ppa50. Estradiol (20 mg) 3-5 days before study increased 6-keto-PGF1 alpha concentrations and decreased Ppa50 at PIO2 of 10, 30, and 50 Torr. Indomethacin added to the perfusate of these lungs reduced 6-keto-PGF1 alpha to undetectable levels and altered the estradiol-induced attenuation, increasing Ppa50 at PIO2 of 10 and 30 Torr, but decreasing Ppa50 at PIO2 of 200 Torr. Despite these effects, Ppa50 remained lower than the values measured in lungs not treated with estradiol. These results suggest that the estradiol-induced attenuation of the hypoxic stimulus-response relationship was mediated only in part by cyclooxygenase products, the net effects of which were vasodilation at PIO2 of 10 and 30 Torr, but vasoconstriction at PIO2 of 200 Torr.

The survival of coxsackievirus B3 was studied under various conditions of incubation. The comparative study demonstrated that coxsackievirus B3 was stable for 24 h (<0.4-log decrease in titer) when suspended at neutral pH (6 or 23°C) in the presence of 0.25% bovine serum albumin in saline regardless of whether the preparations were subjected to evaporation. Bovine serum albumin provided increased stability to the virus for each of the conditions tested. At 37°C, evaporation greatly reduced the virus infectivity between 6 and 20 h of incubation. Nevertheless, coxsackievirus B3 was found to be stable for at least 24 h under conditions similar to those of a household environment, and its presence represents a potential biohazard to nonimmune persons. These data provide a rationale for using coxsackievirus B3 as a model for investigating the role of environmental surfaces in the transmission of enteroviral diseases.