title: Mitochondrial trafficking through Rhot1 is involved in the aggregation of germinal granule components during primordial germ cell formation in Xenopus embryos.
abstract: In many animals, the germ plasm is sufficient and necessary for primordial germ cell (PGC) formation. It contains germinal granules and abundant mitochondria (germline-Mt). However, the role of germline-Mt in germ cell formation remains poorly understood. In Xenopus, the germ plasm is distributed as many small islands at the vegetal pole, which gradually aggregates to form a single large mass in each of the four vegetal pole cells at the early blastula stage. Polymerized microtubules and the adapter protein kinesin are required for the aggregation of germ plasm. However, it remains unknown whether germline-Mt trafficking is important for the cytoplasmic transport of germinal granules during germ plasm aggregation. In this study, we focused on the mitochondrial small GTPase protein Rhot1 to inhibit mitochondrial trafficking during the germ plasm aggregation. Expression of Rhot1ΔC, which lacks the C-terminal mitochondrial transmembrane domain, inhibited the aggregation of germline-Mt during early development. In Rhot1-inhibited embryos, germinal granule components did not aggregate during cleavage stages, which reduced the number of PGCs on the genital ridge at tail-bud stage. These results suggest that mitochondrial trafficking is involved in the aggregation of germinal granule components, which are essential for the formation of PGCs.
authors: Department of Life Science, Faculty of Science, Rikkyo University, Tokyo, 171-8501, Japan.
authors: Haru
authors: H
authors: Tada
authors: Department of Life Science, Faculty of Science, Rikkyo University, Tokyo, 171-8501, Japan.
authors: Yuya
authors: Y
authors: Taira
authors: Department of Life Science, Faculty of Science, Rikkyo University, Tokyo, 171-8501, Japan.
authors: Keisuke
authors: K
authors: Morichika
authors: Department of Life Science, Faculty of Science, Rikkyo University, Tokyo, 171-8501, Japan. tkinoshita@rikkyo.ac.jp.
authors: Tsutomu
authors: T
authors: Kinoshita
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology*; D047108:Embryonic Development / Q000502:physiology; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism*; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D063154:Mitochondrial Dynamics / Q000502:physiology*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D024101:Mitochondrial Proteins; D029867:Xenopus Proteins; D020741:rho GTP-Binding Proteins
keywords: 
  Xenopus laevis
  ; Miro; germ plasm; mitochondria; primordial germ cell