Analysis of expression levels of E۲F transcription factors in lineage negative hematopoietic stem cells of young and old mice

Background and aims: The E۲F family of transcription factors is encoded by at least eight genes, E۲F۱-۸. These proteins are important targets of the retinoblastoma protein (RB) contributed in regulation of transcription, cell cycle and apoptosis. The aim of this study was to investigate the expression levels of E۲F protein family including E۲F۱, E۲F۲, E۲F۷, E۲F۸ and RB۱ in the lineage negative (Lin-) hematopoietic stem cells (HSCs) of young and aged black mice using Real Time RT-PCR and western blot techniques. Methods: Lin- HSCs of ۴ young (۷-۱۰ weeks old) and ۳ aged (۷۶ weeks old ) mice have been isolated from their bone marrow cells using MACS column and after RNA extraction of culturing cells and cDNA preparation, samples were then analyzed by Real Time RT- PCR and western blot techniques. Results: The E۲F۷ and E۲F۸ expression levels of the Lin- HSCs of old mice were only the transcriptional factors significantly decreased when compared with young mice. In conclusion: It seems the functional roles of important E۲F۷ and E۲F۸ transcription factors in moderating potentially destructive activity of E۲F۱ and regulation of cell cycle have been diminished in Lin- HSCs of aged mice. Hence, the apoptotic activity of the E۲F۱ would affect to the most HSCs, reinforcing bone marrow to proliferate the HSCs in old mice. However, Real Time RT-PCR data showed that the expression level of the E۲F۱ in those cells was not increased significantly as expected. This is the first report in this regard and further investigation with more samples need to reconfirm these data.

کلیدواژه ها:

E۲Fs ، lineage negative ، HSCs ، Expression levels