Wei Ke-Hsuan, Liu I-Hsuan
Department of Animal Science and Technology, National Taiwan University, Taipei, Taiwan.
Department of Animal Science and Technology, National Taiwan University, Taipei, Taiwan; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan.
Theriogenology. 2014 Jun;81(9):1275-85.e1-2. doi: 10.1016/j.theriogenology.2014.02.009. Epub 2014 Feb 14.
Early in embryonic development, primordial germ cells (PGCs) are specified and migrate from the site of their origin to where the gonad develops, following a specific route. Heparan sulfate glycosaminoglycans (HS-GAGs) are ubiquitous in extracellular matrix and the cell surface and have long been speculated to play a role during the migration of PGCs. In line with this speculation, whole-mount immunohistochemistry revealed the existence of HS-GAGs in the vicinity of migrating PGCs in early zebrafish embryos. To examine the roles of HS-GAGs during PGC migration, zebrafish heparanase 1 (hpse1), which degrades HS-GAGs, was cloned and overexpressed specifically in PGCs. The guidance signal for the migration of PGCs was disrupted with the overexpression of hpse1, as cluster formation and marginal localization at the blastoderm were significantly perturbed at 6 hours postfertilization. Furthermore, the number of PGCs was significantly decreased with the lack of vicinal HS-GAGs, as observed in the whole-mount in situ hybridization and quantitative PCR of the PGC marker gene vasa. Terminal deoxynucleotidyl transferase dUTP nick-end labeling indicated significantly increased apoptosis in PGCs overexpressing hpse1, suggesting that HS-GAGs contribute to the maintenance of PGC survival. In conclusion, HS-GAGs play multifaceted roles in PGCs during migration and are required both for guidance signals and multiplication of PGCs.
在胚胎发育早期，原始生殖细胞（PGCs）被特化，并沿着特定路径从其起源部位迁移至性腺发育的位置。硫酸乙酰肝素糖胺聚糖（HS-GAGs）在细胞外基质和细胞表面广泛存在，长期以来一直被推测在PGCs迁移过程中发挥作用。与这一推测相符的是，整体免疫组织化学显示在早期斑马鱼胚胎中，迁移的PGCs附近存在HS-GAGs。为了研究HS-GAGs在PGC迁移过程中的作用，克隆了可降解HS-GAGs的斑马鱼乙酰肝素酶1（hpse1），并使其在PGCs中特异性过表达。由于受精后6小时胚盘处的细胞团形成和边缘定位受到显著干扰，hpse1的过表达破坏了PGCs迁移的引导信号。此外，如在PGC标记基因vasa的整体原位杂交和定量PCR中所观察到的，邻近HS-GAGs的缺失导致PGCs数量显著减少。末端脱氧核苷酸转移酶dUTP缺口末端标记表明，过表达hpse1的PGCs中凋亡显著增加，这表明HS-GAGs有助于维持PGC的存活。总之，HS-GAGs在PGCs迁移过程中发挥多方面作用，对PGCs的引导信号和增殖都是必需的。
