Transgenerational analysis of H3K4me3 and H3K27me3 by ChIP-Seq links epigenetic inheritance to metabolism

Histone methylation is a kind of important epigenetic modification which occurs on the lysine residue or arginine residue of histone tails（Zhang and Reinberg,2001）.It takes part in multiple biological processes,including gene expression,genomic stability,stem cell maturity,genetic imprinting,mitosis and development（Fischle et al.,2005）.

Comparison of three fluorescence labeling and tracking methods of endothelial progenitor cells in laser-injured retina

AIM： To compare three kinds of fluorescent probes for in vitro labeling and in vivo tracking of endothelial progenitor cells（EPCs） in a mouse model of laser-induced retinal injury.METHODS： EPCs were isolated from human umbilical cord blood mononuclear cells and labeled with three different fluorescent probes： 5-（and-6）-carboxyfluorescein diacetate succinimidyl ester（CFSE）, 1,1′-dilinoleyl-3,3,3′,3′-tetramethylindo-carbocyanine perchlorate linked acetylated low-density lipoprotein（Di I-Ac LDL）, and green fluorescent protein（GFP）. The fluorescent intensity of EPCs was examined by confocal microscopy. Survival rate of labeled EPCs was calculated with trypan blue staining, and their adhesive capability was assessed. A mouse model of retinal injury was induced by laser, and EPCs were injected into the vitreous cavity. Frozen section and fluorescein angiography on flat-mounted retinal samples was employed to track the labeled EPCs in vivo.RESULTS： EPCs labeled with CFSE and Di I-Ac LDL exhibited an intense green and red fluorescence at the beginning; the fluorescence intensity decreased gradually to 20.23% and 49.99% respectively, after 28 d. On the contrary, the florescent intensity of GFP-labeled EPCs increased in a time-dependent manner. All labeled EPCs showed normal morphology and no significant change in survival and adhesive capability. In the mouse model, transplantation of EPCs showed a protective effect against retinal injury. EPCs labeled with CFSE and Di I-Ac LDL were successfully tracked in mice during the development of retinal injury and repair; however, GFP-labeled EPCs were not detected in the laser-injured mouse retina.CONCLUSION： The three fluorescent markers used in this study have their own set of advantages and disadvantages. CFSE and Di I-Ac LDL are suitable for short-term EPClabeling, while GFP should be used for long-term labeling. The choice of fluorescent markers should be guided by the purpose of the study.

The Three Links policy and stock returns

This study examines whether the Three Links(3L)policy affected stock returns before,during and after the 2008 Taiwan leadership election.The evidence shows that companies in the industries benefitting from(being damaged by)the 3L policy earned posi-tive(negative)cumulative abnormal returns.Although the polit-ical party connection/affiliation seems to have had an impact as well,it was not persistent.When both factors–the policy effect and the political connection effect–are considered together,we find that the policy effect persisted during the election,while the political connection effect did not.It is obvious that the policy effect is a powerful factor explaining changes of stock returns during the 2008 leadership election in China’s Taiwan.