PGC-1 alpha isoforms and muscle hypertrophy

An alternative promoter of the PGC-1alpha gene gives rise to three new PGC-1alpha isoforms refered to as PGC-1a2 (A2), PGC-1a3 (A3) and PGC-1a4 (A4). The proximal PGC-1 alpha promotor transcribes the canonical PGC-1 alpha which is refered to as PGC-1a1 (A1).G1/G2/G3 samples refer to the Green fluorescent protein (GFP) control samples used in this experiment. Forced expression of the PGC-1a4 isoform results in muslce hypertrophy associated with increased IGF-1 signaling and repression of myostatin signaling. Mouse primary myoblasts isolated from C57BL/6 mice were differentiated in vitro. Fully differentiated myotubes were transduced with adenoviral vectors expressing GFP (as control) or each of the PGC-1alpha isoforms originating from the proximal or alternative promotor.

过氧化物酶体增殖物激活受体γ辅激活因子1α（PGC-1alpha）基因的可变启动子可产生三种新型PGC-1alpha转录本异构体，分别命名为PGC-1α2（A2）、PGC-1α3（A3）与PGC-1α4（A4）。近端PGC-1alpha启动子转录得到经典型PGC-1alpha，即PGC-1α1（A1）。G1、G2、G3样本为本实验中使用的绿色荧光蛋白（GFP）对照样本。过表达PGC-1α4异构体可诱导肌肉肥大，该过程伴随胰岛素样生长因子1（IGF-1）信号通路激活与肌抑素（myostatin）信号通路抑制。本研究从C57BL/6小鼠体内分离得到原代成肌细胞并开展体外分化，随后将完全分化的肌管用表达GFP（作为对照）或源自近端或可变启动子的各类PGC-1alpha异构体的腺病毒载体进行转导。