1. Affinity purified anti-renin was used to detect renin-immunoreactive proteins in cloned colonies of Escherichia coli containing recombinant mouse submandibular gland cDNA inserted at the Pst I site of plasmid pBR322. 2. Two colonies were detected which reacted positively with anti-renin. 3. These colonies contained a single protein that could be immunoprecipitated with anti-renin and cDNA of more than 500 base-pairs in length which was capable of inter-colony hybridization in the single-stranded form and had similar Hin fI restriction sites. 4. Sequencing is being performed on the cDNA after having been subcloned in M13mp 7.1.
1. A cDNA clone library was constructed from male mouse submandibular gland poly(A) + RNA. 2. A 500 base-pair sequence consisting of a 3′ untranslated region plus a 447 base-pair region coding for an amino acid sequnce having 57% homology with the C -terminal 149 amino acids in the 230 amino acid chain of porcine pancreatic kallikrein was identified. 3. The sequence was strongly but not completely homologous with known mouse submandibular gland serine proteinase sequences and represents the first report of a DNA base sequence for a serine proteinase. It may be part of the gene coding for kallikrein. 4. The biosynthetic pathway for renin was established by continuous-labelling, pulse-chase and cell-free translation studies of submandibular gland tissue from normal and testosterone-induced mice. 5. Renin was synthesized as a mol. wt. 46 000 preprorenin which is likely to be hydrolysed before completion of the nascent chain. A prorenin of mol. wt. 44 500, pI 6.4 was identified and shown to be rapidly converted into a mol. wt. 40 000, pI 6.2 renin, which was then converted more slowly into forms of mol. wt. 35 500, pI 5.6 and mol. wt. 34 000, pI 5.4.
1. By the use of a mechanical graded sieving technique a high yield of isolated glomeruli has been obtained from rat kidney. 2. Microscopy and renin assay have shown the presence of renin-containing juxtaglomerular cells attached to these glomeruli. 3. The viability of isolated glomeruli has been confirmed by the ability of the cells to survive and divide in tissue culture and by their exclusion of vital dyes. 4. In superfusion after washout of extracellular renin, the glomeruli actively release constant amounts of renin over 3 h in direct proportion to the number superfused. 5. Decreasing sodium concentration from 140 to 110 mol/l with constant osmolarity of 305 mosmol/l stimulated renin release by a direct effect on juxtaglomerular cells. 6. Catecholamines stimulated renin release in vitro in proportion to the potency of their action on β-adrenoreceptors. 7. The system of superfusion of isolated glomeruli provides a technique for studying the influence of mediators leading to renin release acting directly on juxtaglomerular cells, independent of pressure change, tubular sodium, the sympathetic nervous system and circulating hormones.