Proximal PASs

Alternative polyadenylation (APA) refers to the regulated selection of polyadenylation sites (PASs) in transcripts, which determines the length of their 3′ untranslated regions (3′UTRs). We have recently shown that SRSF3 and SRSF7, two closely related SR proteins, connect APA with mRNA export.

34p viarchimedes 26-01-2022 10 0   Download

IF is produced in the gastric parietal cells of the fundus and body of the stomach, and its secretion parallels that of hydrochloric acid. The IF-cobalamin complex passes to the ileum, where IF attaches to a specific receptor (cubilin) on the microvillus membrane of the enterocytes. Cubilin is also present in yolk sac and renal proximal tubular epithelium. Cubulin appears to traffic by means of amnionless (AMN), an endocytic receptor protein that directs sublocalization and endocytosis of cubulin with its ligand IF-cobalamin complex.

6p thanhongan 07-12-2010 51 3   Download

The following mechanisms are involved. Glomerular filtration. The rate at which a drug enters the glomerular filtrate depends on the concentration of free drug in plasma water and on its molecular weight. Substances that have a molecular weight in excess of 50 000 are excluded from the glomerular filtrate while those of molecular weight less than 10 000 (which includes almost all drugs)21 pass easily through the pores of the glomerular membrane. Renal tubular excretion. Cells of the proximal renal tubule actively transfer strongly charged molecules from the plasma to the tubular fluid.

19p bigbaby87 03-09-2010 109 14   Download