Carvalho Cátia A, Abu-Shach Ulrike Bening, Raju Asha, Vershinin Zlata, Levy Dan, Boxem Mike, Broday Limor
Department of Cell and Developmental Biology, Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel.
The Shraga Segal Department of Microbiology, Immunology and Genetics, Ben-Gurion University of the Negev, Be'er-Sheva, Israel.
PLoS Biol. 2025 Jan 6;23(1):e3002980. doi: 10.1371/journal.pbio.3002980. eCollection 2025 Jan.
Sumoylation is a posttranslational modification essential for multiple cellular functions in eukaryotes. ULP-2 is a conserved SUMO protease required for embryonic development in Caenorhabditis elegans. Here, we revealed that ULP-2 controls germline development by regulating the PHD-SET domain protein, SET-26. Specifically, loss of ULP-2 results in sterility and a progressive elevation of global protein sumoylation. In the germline of ulp-2 null mutant, meiosis is arrested at the diplotene stage and the cells in the proximal germline acquire a somatic fate. Germline RNAseq analysis revealed the down-regulation of numerous germline genes in ulp-2 mutants, whereas somatic gene expression is up-regulated. To determine the key factors that are regulated by ULP-2, we performed a yeast two-hybrid screen and identified the histone methylation reader, SET-26 as a ULP-2 interacting protein. Loss of SET-26 enhanced the sterility of ulp-2 mutant animals. Consistently, SET-26 is sumoylated and its sumoylation levels are regulated by ULP-2. Moreover, we detected a reduction in H3K4 tri-methylation (H3K4me3) histone levels bound to SET-26 in the ulp-2 mutant background suggesting a dependence of this histone reader on balanced sumoylation. Finally, a comparative proteomics screen between WT and ulp-2 loss of activity identified the predicted methyltransferase SET-27 as a ULP-2-dependent SET-26-associated protein. SET-27 knockout genetically interacts with ULP-2 in the germline, but not with SET-26. Taken together, we revealed a SUMO protease/H3K4me3 histone reader axis which is required for the maintenance and regulation of germline development.
SUMO化是真核生物中多种细胞功能所必需的一种翻译后修饰。ULP-2是秀丽隐杆线虫胚胎发育所需的一种保守的SUMO蛋白酶。在此，我们揭示了ULP-2通过调节PHD-SET结构域蛋白SET-26来控制生殖系发育。具体而言，ULP-2的缺失导致不育以及整体蛋白SUMO化水平的逐渐升高。在ulp-2基因敲除突变体的生殖系中，减数分裂停滞在双线期，近端生殖系中的细胞获得体细胞命运。生殖系RNA测序分析显示ulp-2突变体中许多生殖系基因下调，而体细胞基因表达上调。为了确定受ULP-2调节的关键因子，我们进行了酵母双杂交筛选，并鉴定出组蛋白甲基化读取器SET-26为与ULP-2相互作用的蛋白。SET-26的缺失增强了ulp-2突变动物的不育性。一致的是，SET-26被SUMO化，其SUMO化水平受ULP-2调节。此外，我们在ulp-2突变背景中检测到与SET-26结合的H3K4三甲基化（H3K4me3）组蛋白水平降低，这表明这种组蛋白读取器依赖于平衡的SUMO化。最后，WT和ulp-2活性丧失之间的比较蛋白质组学筛选确定预测的甲基转移酶SET-27为ULP-2依赖的SET-26相关蛋白。SET-27基因敲除在生殖系中与ULP-2发生遗传相互作用，但不与SET-26发生相互作用。综上所述，我们揭示了一条SUMO蛋白酶/H3K4me3组蛋白读取器轴，它是维持和调节生殖系发育所必需的。
