Stanniocalcin (STC) is a polypeptide hormone first discovered in fish and more recently in mammals. In mammals, the STC gene is widely expressed and the hormone is involved in a variety of functions, but STC does not normally circulate in the blood. In both kidney and gut, STC regulates phosphate fluxes across the transporting epithelia, whereas in brain it protects neurons against cerebral ischemia and promotes neuronal cell differentiation. However, the gene is most highly expressed in ovary and expression is dramatically up‐regulated by both pregnancy and nursing. STC mRNA levels are also high in the developing mouse embryo, but literally nothing is known of the tissue pattern of gene expression. Therefore, the aim of this study was to map the temporal and spatial patterns of gene expression during mouse embryologic development, starting with the urogenital system where the gene is so highly expressed in adults. STC mRNA was evident as early as E10.5 in both the mesonephros and genital ridge. Between E10.5 and 14.5 in developing kidney, STC was produced in undifferentiated mesenchyme cells and sequestered by ureteric bud epithelial cells that did not express the gene but nonetheless contained high levels of STC protein. Thereafter, the distribution pattern resembled that in adults such that gene expression predominated in collecting duct cells, whereas protein was present in most nephron segments. The pattern of gene expression during gonadal development was sexually dimorphic. In males, expression was first evident on E12.5 in interstitial mesenchyme cells surrounding the developing sex cords, whereas the protein accumulated in developing gonocytes within the sex cords that did not express the gene. This pattern became more pronounced over the course of gestation. In contrast, ovarian gene expression was only weakly evident during development. Collectively, the evidence suggests that in addition to its regulatory effects in adults, STC has novel and distinctive roles in the mesenchymal‐epithelial interactions that are vital to normal organogenesis. © 2001 Wiley‐Liss, Inc.

No abstract

These findings suggest that STC may be of unique importance to neonates. They also suggest that changes in dietary calcium and phosphate can alter renal levels of STC gene expression, but that these effects vary between the early and late segments of the collecting duct.

To address a growing need to make research trainees in physiology comfortable with the tools of molecular biology, we have developed a laboratory-intensive course designed for graduate students. This course is offered to a small group of students over a three-week period and is organized such that comprehensive background lectures are coupled with extensive hands-on experience. The course is divided into seven modules, each organized by a faculty member who has particular expertise in the area covered by that module. The modules focus on basic methods such as cDNA subcloning, sequencing, gene transfer, polymerase chain reaction, and protein and RNA expression analysis. Each module begins with a lecture that introduces the technique in detail by providing a historical perspective, describing both the uses and limitations of that technique, and comparing the method with others that yield similar information. Most of the lectures are followed by a laboratory session during which students follow protocols that were carefully designed to avoid pitfalls. Throughout these laboratory sessions, students are given an appreciation of the importance of proper technique and accuracy. Communication among the students, faculty, and the assistant coordinator is focused on when and why each procedure would be used, the importance of each step in the procedure, and approaches to troubleshooting. The course ends with an exam that is designed to test the students' general understanding of each module and their ability to apply the various techniques to physiological questions.