植物Trihelix转录因子家族研究进展

Trihelix转录因子家族是一类最近才被引发关注的基因家族, 其因在DNA结合结构域含有3个串联的螺旋结构(螺旋-环-螺旋-环-螺旋)而得名, 该结构域能特异地与DNA序列上的光应答元件GT元件结合, 所以该家族也被称为GT因子家族。在研究早期, 人们对该基因家族的认识只局限于它们对光依赖型靶基因的调控, 而最近10年的研究表明, 该家族基因在植物的花、气孔、表皮毛、胚胎和种子的发育等不同生长发育过程中, 以及在病害、盐胁迫、干旱胁迫和冷胁迫等生物胁迫和非生物胁迫应答过程中都扮演重要角色。文章主要从Trihelix转录因子家族的结构特点、分类以及最新的功能研究进展进行详细综述。     

Implication of STAT1 and STAT3 transcription factors in the response to superantigens

The activation of STAT1 and STAT3 in response to SEB was analyzed in spleen of Balb/c mice. The intraperitoneal injection of the superantigen SEB activated STAT1 and STAT3 in spleen. Activated STAT1 almost completely disappeared in 24 h even though activated STAT3 was present for more than 48 h after SEB injection. Cyclosporine A was able to block the initial STAT1 activation, but STAT3 activation was only partially affected. SEB also increased the mRNA levels for STAT1, STAT3 and SOCS1. When a second injection with SEB was given 72 h after the first stimulus, STAT1 activation was much lower than that observed after the first stimulation with SEB and no increase in the STAT1 mRNA level was observed. Nevertheless, after this second injection, STAT3 was again activated without any significant interference from the first stimulus and the STAT3 and SOCS1 mRNA levels again increased. These data indicate that a first stimulation with superantigen re-programs cells so that they respond to a second stimulation in a different way. Understanding the mechanisms implicated in this re-programming is basic for designing therapeutic strategies in processes such as septic shock.