NANOG changes in mouse kidneys with age.

NANOG is essential for mouse and human embryonic stem cell (ESC) pluripotency and selfrenewal. It is also expressed in several adult murine tissues as shown by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. However, human NANOG transcripts have been isolated from adult bone marrow (EST; GenBank accession no. BF893620). Here, we study the NANOG gene expression profile in isolated mouse renal papillary cells by Northern blot and RT-PCR. The whole RNA of mouse renal cells was obtained from fresh renal tissues, renal tissues infused by phosphate-buffered saline (PBS), and isolated renal papillary cells of mouse, respectively, as well as the renal papillary tissue from 18.5 days postcoitum (d.p.c.; fetal), 1-2-week-old (young), 1-8-month-old (adult), and 24-month-old (aging) mice. Our analysis shows that a very low expression level was detected in mouse renal tissues, and the renal papillary cells express more than other tissues as determined with Northern blot and RT-PCR. These data suggest that the kidney has its own cells expressing NANOG, and loss of NANOG expression occurs in an age-dependent manner in the kidney, either due to developmental factors or aging, particularly in renal papillary tissue.