The Change of Telomerase Activity in the Developmental Stages of the Rat Urinary System

Lee, Sang Don; Bahk, Jong Yoon

Abstract

PURPOSE: Telomeres define the natural ends of linear chromosomes and their sequence organization is highly conserved in the majority of eukaryotes. Telomerase is a ribonucleoprotein involved in maintaining telomere length in stem cells and immortal and actively dividing cells. If there lacks telomerase in cell, length of telomere will be shortened, and results in cell death. We investigated the changes of telomerase activity in the developmental stages of rat urinary system.
MATERIALS AND METHODS
Organs(kidney, ureter and bladder) were aseptically removed from Sprague-Dawley rats of fetal(17-day-gestation), growing(1, 2, 3, 4, and 6-week-old) and adult period(12-week-old). Samples for telomerase activity were frozen on liquid nitrogen immediately after sacrifice, and stored until the use at -750C for measurement of telomerase activity. Telomerase activity was measured by a PCR-based telomeric repeat amplification protocol(TRAP) assay. Telomerase activity was quantitated with a phosphoimager(GS525 Molecular Imager System, Bio-Rad Laboratories, Hercules, California, USA).
RESULTS
Telomerase activities in the kidney were highly expressed at the fetal period, however they were significantly decreased since 1week after birth and maintained weakly until adult period. Telomerase activities of the bladder and ureter showed active expression throughtout whole life. When comparing the telomerase activities of the ureter and bladder to those of the kidney, the ureter and bladder showed higher acitivities than the kidney throughtout whole life except fetal period.
CONCLUSIONS
There may be a developmental and tissue-specific regulation of telomerase in the urinary system of rat and an active mechanism for maintaining telomeres in the ureter and bladder after birth.