Mouse submaxillary gland renin. Purification and properties of minor forms, which include several differently processed forms of the major gene product and a second gene product

Genetic regulation of salivary proteins in rodents

The presence of a protein in the cell is the result of a complex pathway that is known by the term gene expression. In this article we review the existing literature on the structure and expression of representative salivary gland genes and their regulated expression during development and upon extracellular stimulation. The expression of one of the "nuclear" protooncogenes, c-fos, in rat parotid glands is also discussed. Finally, we present some suggestions for future studies that will help to understand the mechanisms leading to gene regulation in rat salivary glands.

Site-specific cleavage of a fusion protein by renin

A double-stranded synthetic oligonucleotide that codes for an amino acid sequence specifically recognized and cleaved by the endopeptidase, renin, was inserted into a plasmid expression vector. The double-stranded oligonucleotide was placed at the junction between the sequences coding for two distinct domains of a fusion protein. The vector used for this analysis expressed a 190-kD Epstein-Barr virus membrane antigen (EBV-MA)-beta-galactosidase (beta-gal) fusion protein (Beisel et al., 1985). The resultant novel protein product expressed by the new construction can be cleaved specifically by renin to yield two distinct polypeptides, EBV-MA and beta-gal, corresponding to the two domains of the original fusion protein product.

Renin heterogeneity in stroke-prone hypertensive and normotensive rats

Six forms of renin are found in the rat kidney. We studied their secretion in renal slices from spontaneously hypertensive stroke-prone rats (SHRSP) and Wistar-Kyoto rats (WKY). Incubation media from renal slices were subjected to isoelectric focusing. Six peaks of renin activity with different isoelectric points were found. The renin concentration of each form was expressed as a percentage of the total recovered from the gel. We established that the forms secreted by renal slices of SHRSP differed from those of WKY: SHRSP slices released a higher proportion of forms focusing at the more acidic pH. The distribution of the six renin forms and of blood pressure (BP) among animals of the F1, F2, and backcross progenies resulting from the cross of SHRSP and WKY rats were studied. In the F1, BP, percentage of renin form 2, and a combination of the percentage of forms 4 + 5 + 6 were intermediate between the parental lines. The backcross rats showed BP and percentages of forms closer to their SHRSP or WKY parent. In the F2, the distribution of BP, percentage of forms 2 and 4 + 5 + 6 take the form of a unimodal distribution with a significantly larger variance than F1. The increase in the correlation between percentage of renin forms and BP, and between renin concentration of BP, in the segregating progenies over that observed in the parental lines and the F1, are support for the hypothesis that these traits are under the control of common genetic mechanisms.

Modification of renin isoelectric heterogeneity in Goldblatt hypertensive rat

Six forms of renin have been described in rat kidney. Different stimuli resulted in secretion of unique profiles of those forms. We studied their storage and secretion in the two-kidney, one-clip Goldblatt hypertensive rat (GHR). Renal venous blood, kidney homogenates, and incubation media from cortical slices were subjected to isoelectric focusing. In all samples tested, six peaks of renin activity were found with isoelectric points at pH 5.90, 5.70, 5.40, 5.20, 5.00, and 4.80. The quantity of renin activity for each form was expressed as a percentage of the total recovered from the gel. In control kidneys the profile of renin stored and that released by in vitro slices were similar. However, in plasma, the percentage of renin focusing at the more basic pH was decreased. This is in agreement with other work showing that the liver removes the more basic forms more rapidly than the acidic forms. The clipped kidney of GHR secreted, both in vivo and in vitro, a profile of renin forms that was significantly different from the control kidney. The difference was expressed by an increase in the secretion of the more acidic forms by the clipped kidney. It is hypothesized that changes in the secretory profile of renin may reflect changes in storage and synthesis of those forms.