Zazueta-Novoa Vanesa, Onorato Thomas M, Reyes Gerardo, Oulhen Nathalie, Wessel Gary M
Department of Molecular Biology, Cellular Biology and Biochemistry, Brown University, 185 Meeting Street, Box G-SFH, Providence, Rhode Island 02912; and.
Department of Natural Sciences, LaGuardia Community College/CUNY, Room M207, 31-10 Thomson Avenue, Long Island City, New York 11101
Biol Bull. 2016 Jun;230(3):209-19. doi: 10.1086/BBLv230n3p209.
Oviparous animals store yolk proteins within the developing oocyte. These proteins are used in gametogenesis and as a nutritional source for embryogenesis. Vitellogenin and the major yolk protein are two of the most important yolk proteins among diverse species of invertebrates and vertebrates. Among the echinoderms, members of the subphyla Echinozoa (sea urchins and sea cucumbers) express the major yolk protein (MYP) but not vitellogenin (Vtg), while an initial report has documented that two Asterozoa (sea stars) express a vitellogenin. Our results show that sea stars contain two vitellogenins, Vtg 1 and Vtg 2, and MYP. In Patiria miniata, these genes are differentially expressed in the somatic and germ cells of the ovary: Vtg 1 is enriched in the somatic cells of the ovary but not in the oocytes, and Vtg 2 accumulates in both oocytes and somatic cells; MYP is not robustly present in either. Remarkably, Vtg 2 and MYP mRNA reappear in larvae; Vtg 2 is detected within cells of the ectoderm, and MYP accumulates in the coelomic pouches, the intestine, and the posterior enterocoel (PE), the site of germ line formation in this animal. Additionally, the Vtg 2 protein is present in oocytes, follicle cells, and developing embryos, but becomes undetectable following gastrulation. These results help elucidate the mechanisms involved in yolk dynamics, and provide molecular information that allows for greater understanding of the evolution of these important gene products.
卵生动物在发育中的卵母细胞内储存卵黄蛋白。这些蛋白质用于配子发生，并作为胚胎发生的营养来源。卵黄原蛋白和主要卵黄蛋白是无脊椎动物和脊椎动物不同物种中最重要的两种卵黄蛋白。在棘皮动物中， Echinozoa亚门（海胆和海参）的成员表达主要卵黄蛋白（MYP）但不表达卵黄原蛋白（Vtg），而一份初步报告记录了两种海星（Asterozoa）表达一种卵黄原蛋白。我们的结果表明，海星含有两种卵黄原蛋白，Vtg 1和Vtg 2，以及MYP。在小红海盘车（Patiria miniata）中，这些基因在卵巢的体细胞和生殖细胞中差异表达：Vtg 1在卵巢的体细胞中富集，但在卵母细胞中不富集，Vtg 2在卵母细胞和体细胞中都有积累；MYP在两者中都不存在。值得注意的是，Vtg 2和MYP mRNA在幼虫中重新出现；Vtg 2在外胚层细胞中被检测到，MYP在体腔囊、肠道和后肠体腔（PE）中积累，PE是这种动物生殖系形成的部位。此外，Vtg 2蛋白存在于卵母细胞、卵泡细胞和发育中的胚胎中，但在原肠胚形成后无法检测到。这些结果有助于阐明卵黄动态变化所涉及的机制，并提供分子信息，以便更好地理解这些重要基因产物的进化。
