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Transient occurrence of vasa-expressing cells in nongenital segments during embryonic development in the oligochaete annelid Tubifex tubifex
| Title: | Transient occurrence of vasa-expressing cells in nongenital segments during embryonic development in the oligochaete annelid Tubifex tubifex |
| Authors: | Oyama, Atsuko Browse this author | | Shimizu, Takashi Browse this author →KAKEN DB |
| Keywords: | Primordial germ cells | | Oligochaete annelid | | Tubifex tubifex | | Embryogenesis | | vasa | | Body segments |
| Issue Date: | Oct-2007 |
| Publisher: | Springer |
| Journal Title: | Development Genes and Evolution |
| Volume: | 217 |
| Issue: | 10 |
| Start Page: | 675 |
| End Page: | 690 |
| Publisher DOI: | 10.1007/s00427-007-0180-1 |
| PMID: | 17851685 |
| Abstract: | The primordial germ cells (PGCs) in the oligochaete annelid Tubifex tubifex are mesodermal in origin and are located in the two midbody segments X and XI in which the testis and the ovary are formed, respectively. To identify a molecular marker for the Tubifex PGCs, we isolated the Tubifex homologue (Ttu-vas) of the Drosophila vasa gene. Using whole-mount in situ hybridization, we examined the spatial expression patterns of Ttu-vas from 1-cell stage through juvenile stage. Ttu-vas mRNA is present as a maternal transcript distributed broadly throughout the early stages. Ttu-vas is expressed in all of the early cleavage blastomeres, in which Ttu-vas RNA associates with mitotic spindles and pole plasms. Expression of Ttu-vas gradually becomes restricted, first to teloblasts, then to their blast cell progeny comprising the germ bands (GBs), and finally to a set of large ventral cells (termed VE cells) in a variable set of midbody segments including the genital segments (X and XI). At the end of embryogenesis, VE cells are confined to genital segments where they are presumably germline precursors in the juvenile. Staining with a cross-reacting anti-Vasa antibody suggested that VE cells express Ttu-vas protein to the same extent irrespective of their positions along the anteroposterior axis. A set of cell ablation experiments suggested that VE cells are derived from the mesodermal teloblast lineage and that the emergence of VE cells takes place independently of the presence of the ectodermal GBs that normally overlay the mesoderm. These results suggest that T. tubifex generates supernumerary presumptive PGCs during embryogenesis whose number is variable among embryos. |
| Rights: | The original publication is available at www.springerlink.com |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/30348 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 清水 隆
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