Germ cell-specific deletion of Pex3 reveals essential roles of PEX3-dependent peroxisomes in spermiogenesis

Peroxisomes are organelles enclosed by a single membrane and are present in various species.The abruption of peroxisomes is correlated with peroxisome biogenesis disorders and single peroxisomal enzyme deficiencies that induce diverse diseases in different organs.However,little is known about the protein compositions and corresponding roles of heterogeneous peroxisomes in various organs.Through transcriptomic and proteomic analyses,we observed heterogenous peroxisomal components among different organs,as well as between testicular somatic cells and different developmental stages of germ cells.As Pex3 is expressed in both germ cells and Sertoli cells,we generated Pex3 germ cell-and Sertoli cell-specific knockout mice.While Pex3 deletion in Sertoli cells did not affect spermatogenesis,the deletion in germ cells resulted in male sterility,manifested as the destruction of intercellular bridges between spermatids and the formation of multinucleated giant cells.Proteomic analysis of the Pex3-deleted spermatids revealed defective expressions of peroxisomal proteins and spermiogenesis-related proteins.These findings provide new insights that PEX3-dependent peroxisomes are essential for germ cells undergoing spermiogenesis,but not for Sertoli cells.

基因调节网络分析Pex3基因与焦虑症相关

目的:以C57BL/6J(B6)和DBA/2(D2)小鼠制备慢性焦虑模型,探究并验证Pex3基因与焦虑症的关系,及该基因表达调节通路。方法:采用数量性状基因座(expression quantitative trait loci, eQTL)分析技术结合基因表达的遗传相关性分析发现新的焦虑症相关基因,并筛选其上游调控位点或下游被调控的基因,最后通过分子生物学方法予以验证。结果:基因表达谱与遗传连锁分析表明Pex3在小鼠海马及杏仁核等焦虑相关脑区高效表达,提示其可能与焦虑症相关,进一步研究发现,在BXD家族的两亲本小鼠焦虑症模型中,Pex3在蛋白水平和mRNA水平的表达均明显下降。因此,筛选Pex3为焦虑症的候选基因。Pex3为顺式调控基因,鉴定了8个邻近Pex3位点的反式QTL的基因,通过进一步排除由于连锁不平衡引起的相关转录物,结果显示Nr3c2和Lrp11[似然比统计值(likelihood ratio statistic, LRS)>10]为Pex3的下游候选基因。最后,用Pex3 siRNA转染HEK 293T细胞,验证沉默Pex3对下游基因的影响,其下游候选基因中Nr3c2是焦虑症相关基因。结论:经验证Pex3为焦虑症相关基因,可能与其下游基因Nr3c2共同参与了焦虑症的发生发展过程。