[Time course of let-7a expression in the cell cycle of human cervical carcinoma HeLa cells]

To investigate the time course of let-7a microRNA expression in the cell cycle of HeLa cells.

HeLa cells were synchronized in G(1), S and G(2)/M phases using double-thymidine block, and the cell cycle phases were defined by flow cytometry. Real-time quantitative RT-PCR was used to examine the expression of let-7a in HeLa cells in different cell cycle phases.

The synchronization rates of G(1), S and G(2)/M phases were 84.81%, 83.65% and 77.69%, respectively. Let-7a was constitutively expressed throughout the cell cycle in HeLa cells, but the expression levels in G(1) and S phases were lower than those in G(2)/M phase.

Cell cycle can significantly influence the expression level of let-7a, which may provide new clues to the understanding of the cell cycle control mechanisms.