Affordable Access

Publisher Website

Asymmetric localization of germline markers Vasa and Nanos during early development in the amphioxus Branchiostoma floridae

Authors
Journal
Developmental Biology
0012-1606
Publisher
Elsevier
Publication Date
Volume
353
Issue
1
Identifiers
DOI: 10.1016/j.ydbio.2011.02.014
Keywords
  • Germline Cell
  • Vasa
  • Nanos
  • Cephalochordate
  • Evolution
Disciplines
  • Biology

Abstract

Abstract The origin of germline cells was a crucial step in animal evolution. Therefore, in both developmental biology and evolutionary biology, the mechanisms of germline specification have been extensively studied over the past two centuries. However, in many animals, the process of germline specification remains unclear. Here, we show that in the cephalochordate amphioxus Branchiostoma floridae, the germ cell-specific molecular markers Vasa and Nanos become localized to the vegetal pole cytoplasm during oogenesis and are inherited asymmetrically by a single blastomere during cleavage. After gastrulation, this founder cell gives rise to a cluster of progeny that display typical characters of primordial germ cells (PGCs). Blastomeres separated at the two-cell stage grow into twin embryos, but one of the twins fails to develop this Vasa-positive cell population, suggesting that the vegetal pole cytoplasm is required for the formation of putative PGCs in amphioxus embryos. Contrary to the hypothesis that cephalochordates may form their PGCs by epigenesis, our data strongly support a preformation mode of germ cell specification in amphioxus. In addition to the early localization of their maternal transcripts in the putative PGCs, amphioxus Vasa and Nanos are also expressed zygotically in the tail bud, which is the posterior growth zone of amphioxus. Thus, in addition to PGC specification, amphioxus Vasa and Nanos may also function in highly proliferating somatic stem cells.

There are no comments yet on this publication. Be the first to share your thoughts.