scholarly journals Zebrafish vasa RNA but Not Its Protein Is a Component of the Germ Plasm and Segregates Asymmetrically before Germline Specification

2000 ◽  
Vol 149 (4) ◽  
pp. 875-888 ◽  
Author(s):  
Holger Knaut ◽  
Francisco Pelegri ◽  
Kerstin Bohmann ◽  
Heinz Schwarz ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Germ Cell ◽  
Germ Plasm ◽  
Primordial Germ Cell ◽  
Subcellular Structure ◽  
Actin Cortex ◽  
Maternal Effect Gene ◽  
Close Proximity ◽  
Hybrid Fish ◽  
Vasa Gene ◽  
Effect Gene

Work in different organisms revealed that the vasa gene product is essential for germline specification. Here, we describe the asymmetric segregation of zebrafish vasa RNA, which distinguishes germ cell precursors from somatic cells in cleavage stage embryos. At the late blastula (sphere) stage, vasa mRNA segregation changes from asymmetric to symmetric, a process that precedes primordial germ cell proliferation and perinuclear localization of Vasa protein. Analysis of hybrid fish between Danio rerio and Danio feegradei demonstrates that zygotic vasa transcription is initiated shortly after the loss of unequal vasa mRNA segregation. Blocking DNA replication indicates that the change in vasa RNA segregation is dependent on a maternal program. Asymmetric segregation is impaired in embryos mutant for the maternal effect gene nebel. Furthermore, ultrastructural analysis of vasa RNA particles reveals that vasa RNA, but not Vasa protein, localizes to a subcellular structure that resembles nuage, a germ plasm organelle. The structure is initially associated with the actin cortex, and subsequent aggregation is inhibited by actin depolymerization. Later, the structure is found in close proximity of microtubules. We previously showed that its translocation to the distal furrows is microtubule dependent. We propose that vasa RNA but not Vasa protein is a component of the zebrafish germ plasm. Triggered by maternal signals, the pattern of germ plasm segregation changes, which results in the expression of primordial germ cell–specific genes such as vasa and, consequently, in germline fate commitment.

Solea senegalensis vasa transcripts: molecular characterisation, tissue distribution and developmental expression profiles

2013 ◽  
Vol 25 (4) ◽  
pp. 646 ◽  
Author(s):  
Tiziana Pacchiarini ◽  
Ismael Cross ◽  
Ricardo B. Leite ◽  
Paulo Gavaia ◽  
Juan B. Ortiz-Delgado ◽  
...  
Keyword(s):  
Germ Cell ◽  
Expression Profiles ◽  
Primordial Germ Cell ◽  
In Situ Hybridisation ◽  
Developmental Expression ◽  
Solea Senegalensis ◽  
Senegalese Sole ◽  
Gonad Differentiation ◽  
Vasa Gene ◽  
Germinal Cells

The Vasa protein is an RNA helicase belonging the DEAD (Asp-Glu-Ala-Asp)-box family. The crucial role played by the vasa gene in the germ-cell lineage of both vertebrates and invertebrates has made this gene a useful molecular marker for germinal cells and a useful tool in surrogate broodstock production using primordial germ cell transplantation. With the aim of establishing a novel approach to improving Solea senegalensis broodstock management, the vasa gene in this species was characterised. Four S. senegalensis vasa transcripts were isolated: Ssvasa1, Ssvasa2, Ssvasa3 and Ssvasa4. Their phylogenetic relationship with other vasa homologues was determined confirming the high degree of conservation of this helicase throughout evolution. Our qPCR results showed that S. senegalensis vasa transcripts are prevalently expressed in gonads, with ovary-specific expression for Ssvasa3 and Ssvasa4. During embryonic and larval development, a switch between the longest and the shortest transcripts was observed. While Ssvasa1 and Ssvasa2 were maternally supplied, Ssvasa3 and Ssvasa4 depended on the de novo expression program of the growing juveniles, suggesting that vasa mRNA could be involved in Senegalese sole gonad differentiation. In situ hybridisation and immunohistochemical analysis performed in 150-days after hatching (DAH) larvae showed vasa product expression in the germinal region of early gonads. In our work we demonstrated the usefulness of Ssvasa mRNAs as molecular markers for primordial germ cells and germinal cells during embryonic development, larval ontogenesis and gonad differentiation. Furthermore, our results confirmed the potential of vasa to help investigate germinal cell biotechnology for Senegalese sole reproduction.

scholarly journals dead end, a Novel Vertebrate Germ Plasm Component, Is Required for Zebrafish Primordial Germ Cell Migration and Survival

2003 ◽  
Vol 13 (16) ◽  
pp. 1429-1434 ◽  
Author(s):  
Gilbert Weidinger ◽  
Jürg Stebler ◽  
Krasimir Slanchev ◽  
Karin Dumstrei ◽  
Clare Wise ◽  
...  
Keyword(s):  
Cell Migration ◽  
Germ Cell ◽  
Germ Plasm ◽  
Primordial Germ Cell ◽  
Dead End ◽  
Germ Cell Migration

scholarly journals Maternal miR-202-5p is required for zebrafish primordial germ cell migration by protecting small GTPase Cdc42

2019 ◽  
Vol 12 (7) ◽  
pp. 530-542 ◽  
Author(s):  
Yilin Jin ◽  
Wei Liu ◽  
Yangxi Xiang ◽  
Wanwan Zhang ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Plasm ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Primordial Germ Cell ◽  
Cell Formation ◽  
Small Gtpase ◽  
Germ Cell Migration ◽  
Direct Target Gene

Abstract In many lower animals, germ cell formation, migration, and maintenance depend on maternally provided determinants in germ plasm. In zebrafish, these processes have been extensively studied in terms of RNA-binding proteins and other coding genes. The role of small non-coding RNAs in the regulation of primordial germ cell (PGC) development remains largely unknown and poorly investigated, even though growing interests for the importance of miRNAs involved in a wide variety of biological processes. Here, we reported the role and mechanism of the germ plasm-specific miRNA miR-202-5p in PGC migration: (i) both maternal loss and knockdown of miR-202-5p impaired PGC migration indicated by the mislocalization and reduced number of PGCs; (ii) cdc42se1 was a direct target gene of miR-202-5p, and overexpression of Cdc42se1 in PGCs caused PGC migration defects similar to those observed in loss of miR-202-5p mutants; (iii) Cdc42se1 not only interacted with Cdc42 but also inhibited cdc42 transcription, and overexpression of Cdc42 could rescue PGC migration defects in Cdc42se1 overexpressed embryos. Thus, miR-202-5p regulates PGC migration by directly targeting and repressing Cdc42se1 to protect the expression of Cdc42, which interacts with actin to direct PGC migration.

scholarly journals Germ plasm localisation dynamics mark distinct phases of transcriptional and post-transcriptional regulation control in primordial germ cells

2020 ◽  
Author(s):  
Fabio M. D’Orazio ◽  
Piotr Balwierz ◽  
Yixuan Guo ◽  
Benjamín Hernández-Rodríguez ◽  
Aleksandra Jasiulewicz ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Plasm ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Somatic Cells ◽  
Chromatin Accessibility ◽  
Post Transcriptional Regulation ◽  
Genome Activation ◽  
Chromatin Opening

SUMMARYIn many animal models, primordial germ cell (PGC) development depends on maternally-deposited germ plasm to avoid somatic cell fate. Here, we show that PGCs respond to regulatory information from the germ plasm in two distinct phases and mechanisms in zebrafish. We show that PGCs commence zygotic genome activation together with the rest of the embryo with no demonstrable differences in transcriptional and chromatin accessibility levels. Thus, cytoplasmic germ plasm determinants only affect post-transcriptional stabilisation of RNAs to diverge transcriptome from somatic cells, which, unexpectedly, also activate germ cell-specific genes. Perinuclear relocalisation of germ plasm is coupled to dramatic divergence in chromatin opening and transcriptome from somatic cells characterised by PGC-specific chromatin topology. Furthermore, we reveal Tdrd7, regulator of germ plasm localisation, as crucial determinant of germ fate acquisition.

scholarly journals AYAM LEHER GUNDUL: SEJARAH, KARAKTERISTIK, DAN KONSERVASI

2020 ◽  
Vol 23 (1) ◽  
pp. 22
Author(s):  
Kostaman T.
Keyword(s):  
Germ Cell ◽  
Primordial Germ Cell

Ayam leher gundul adalah ayam asli/lokal Indonesia yang belum banyak diketahui informasinya dalam halsejarah, potensi, dan karakteristik; sehingga belum dimanfaatkan secara optimal. Ciri yang paling menonjoldari ayam leher gundul adalah tidak mempunyai bulu dibagian lehernya. Untuk mempertahankannya, metode konservasi yang telah dilakukan oleh Balai Penelitian Ternak (Balitnak) adalah dengan memelihara ternak hidup, akan tetapi dengan keterbatasan sarana dan prasarana tidak dapat dilanjutkan. Data performan ayam leher gundul yang dipelihara di Balitnak sudah terkumpul dan ditabulasi. Alternatif konservasi yang dilakukan oleh Balitnak untuk mempertahankan plasma nutfah ayam leher gundul adalah berupa primordial germ cell (PGC) yang dibekukan pada suhu -196 oC yang sewaktu-waktu dibutuhkan dapat ditransfer ke embrio resipien. Sumber PGC yang di koleksi adalah dari darah dan gonad embrio. Berdasarkan potensi yang dimilikinya, ayam leher gundul memiliki performan yang baik, sehingga dapat dimanfaatkan sebagai ayam lokal penghasil daging dan telur. Tulisan ini diharapkan dapat bermanfaat sebagai data pendukung bagi upaya pelestarian dan pengembangan ayam-ayam lokal yang ada di Indonesia, khususnya ayam leher gundul dan umumnya ayam-ayam lokal Indonesia lainnya.

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