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New proposals for the equation of state of four- and five-dimensional hard-hypersphere mixtures in terms of the equation of state of the corresponding monocomponent hard-hypersphere fluid are introduced. Such proposals (which are constructed in such a way so as to yield the exact third virial coefficient) extend, on the one hand, recent similar formulations for hard-disk and (three-dimensional) hard-sphere mixtures and, on the other hand, two of our previous proposals also linking the mixture equation of state and the one of the monocomponent fluid but unable to reproduce the exact third virial coefficient. The old and new proposals are tested by comparison with published molecular dynamics and Monte Carlo simulation results and their relative merit is evaluated.

Uteroglobin, a progesterone-binding secretory protein, was shown to bind retinoic acid and retinol in a non-saturable manner, at least up to concentrations of retinoids of 20 microM. Binding is increased about 10-fold by previous reduction of uteroglobin with 10 mM dithiothreitol and it is not affected by previous saturation of the progesterone binding site, suggesting different binding sites for the steroid and the retinoids. The results are discussed in relation to a possible physiological role for this protein.

Transgenic mice bearing two fragments of the rabbit uteroglobin 5'-flanking region fused to the new reporter gene (pac) encoding puromycin N-acetyltransferase (PAC) showed a different pattern of expression. Transgenic lines (C0.4) harboring a 404-bp fragment (-396/+8) had a uterus-specific expression slightly inducible by estrogen, lacking detectable expression in other tissues where the uteroglobin-encoding gene is naturally expressed in rabbit. Transgenic lines (C3.2) bearing a longer fragment of 3.2-kb (-3254/+8) showed hormonally regulated expression in the uterus and the male genital tract, and detectable expression in the lung. In addition, the nonstimulated uterine expression of the transgene was higher in C0.4 lines than in C3.2 lines. It could be concluded that all sequences required for uterus-specific expression should be present within the 404-bp fragment, and that other upstream (-396) sequences are responsible for expression in the lung and male genital tract, as well as for a possible down modulation of expression in the uterus.

By means of a DNA-cellulose competitive binding assay, we have studied the interaction of the estrogen receptor with genomic fragments of the estrogen responsive rabbit uteroglobin gene. The fragments spanned from 3255 bp upstream to 1754 bp downstream of the initiation site. Only a fragment (-396/+8) showed strong affinity for the receptor. Within this fragment a unique palindromic sequence (GGTCAccaTGCCC) was found which is very similar to the canonical consensus sequence for the estrogen receptor. A synthetic oligonucleotide of that structure specifically competed for the binding of the receptor to DNA-cellulose.

Double-stranded cDNA was synthesized from partially purified uteroglobin mRNA from rabbit lung. A cDNA coding for lung uteroglobin was then cloned in the plasmid pUC18 and both the nucleotide sequence and the derived amino acid sequence were determined. This allowed us to demonstrate unequivocally that uteroglobins from lung and uterus are identical proteins.

Purified Clara cell secretory protein (CCSP) from rabbit lung was analyzed by SDS gel electrophoresis, and immunoblotting with a specific anti-uteroglobin antibody as well as for its ability to bind [3H]progesterone. The results obtained indicate that proteins CCSP and uteroglobin are identical.