Leber’s Hereditary Optic Neuropathy mutations may affect cell cycle and DNA replication in NT2 cells.

Abstract

Abstract: : Purpose: To further understand the pathophysiological mechanisms of LHON–specific effects in mitochondrial cybrids and controls in the NT2 nuclear background using microarray technology. Methods: Cybrids were created with both normal and LHON mutant mitochondria. Microarray was performed using Affymetrix’s Human U95Av2 chips. Data was analyzed using D–chip and Onto–Express. Results: Using microarray, we have identified genes that are underexpressed in LHON–NT2 cells that are involved in the cell cycle and DNA replication. These include genes that take–part in the transition from G1 to S phase (CDC7) and replication of DNA (MCM3 and 6). One gene that was found to be overexpressed in LHON–NT2 cells, CDKN1C, is a negative regulator of cell proliferation, thus its overexpression may prevent cells from dividing. Conclusion: Previously, we have shown that the yield of NT2 cells with LHON mutations during differentiation was less than controls, by 30%, possibly indicating either decreased proliferative potential or increased cell death. The results indicate that the decreased yield of LHON–NT2 cells following differentiation is most likely caused by decreased proliferative capability, rather than increased cell death. How the expression levels of these genes is affected by LHON mutations is unclear.

Keywords: mitochondria • gene microarray • proliferation