Biology subjects

Banisch, T. U.

Publications and source records attributed to Banisch, T. U..

3 recordsLinked to original sources

bioRxiv2020

A transitory signaling center controls timing of primordial germ cell differentiation

Organogenesis requires exquisite spatio-temporal coordination of cell morphogenesis, migration, proliferation and differentiation of multiple cell types. For gonads, this involves complex interactions between somatic and germline tissues. During Drosophila ovary morphogenesis primordial germ cells (PGCs) are either sequestered in stem cell niches and maintained in an undifferentiated, germline stem cell state, or transition directly towards differentiation. Here, we identify a mechanism that links hormonal triggers of somatic tissue morphogenesis with PGC differentiation. An early ecdysone pulse initiates somatic swarm cell (SwC) migration, positioning them close to PGCs. A second hormone peak activates Torso-like signal in SwCs, which stimulates the Torso RTK signaling pathway in PGCs promoting their differentiation by de-repression of the differentiation gene bag of marbles. Thus, systemic temporal cues generate a transitory signaling center that coordinate ovarian morphogenesis with stem cell self-renewal and differentiation programs, a concept applicable broadly to the integration of stem cells and their niches. HIGHLIGHTSO_LISteroid pulses coordinate gonadogenesis, stem cell self-renewal and differentiation C_LIO_LIAn early steroid pulse initiates migration of Swarm Cells, a transitory support cell type C_LIO_LIA late steroid pulse induces Torso-like expression, a Torso receptor tyrosine kinase (RTK) activator, in Swarm Cells C_LIO_LITorso RTK signaling in primordial germ cells activates the key differentiation gene bam by relieving Kruppel-mediated repression C_LI

developmental biology↗

bioRxiv2019

Zebrafish dazl regulates cystogenesis upstream of the meiotic transition and germline stem cell specification and independent of meiotic checkpoints.

Fertility and gamete reserves are maintained by asymmetric divisions of the germline stem cells to produce new stem cells or daughters that differentiate as gametes. Before entering meiosis, differentiating germ cells (GCs) of sexual animals typically undergo cystogenesis. This evolutionary conserved process involves synchronous and incomplete mitotic divisions of a germ cell daughter (cystoblast) to generate sister cells connected by stable intercellular bridges that facilitate exchange of materials to support a large synchronous population of gamete progenitors. Here we investigate cystogenesis in zebrafish and identified Deleted in azoospermia (Dazl), a conserved vertebrate RNA binding protein as a regulator of this process. Analysis of dazl mutants revealed an essential role for Dazl in regulating incomplete cytokinesis and germline cyst formation before the meiotic transition. Accordingly, dazl mutant GCs form defective ring canals, and ultimately remain as individual cells that fail to differentiate as meiocytes. In addition to promoting cystoblast divisions and meiotic entry, dazl function is required upstream of germline stem cell establishment and fertility. Summary StatementWe show that zebrafish dazl is required for incomplete cytokinesis to generate germline cysts during cystogenesis, acts upstream of germline stem cell establishment, and is required for meiosis, and fertility.

developmental biology↗

bioRxiv2019

A single cell atlas of the developing Drosophila ovary identifies follicle stem cell progenitors

Addressing the complexity of organogenesis at a system-wide level requires a complete understanding of adult cell types, their origin and precursor relationships. The Drosophila ovary has been a model to study how coordinated stem cell units, germline and somatic follicle stem cells, maintain and renew an organ. However, lack of cell-type specific tools have limited our ability to study the origin of individual cell types and stem cell units. Here, we use a single cell RNA sequencing approach to uncover all known cell types of the developing ovary, reveal transcriptional signatures, and identify cell type specific markers for lineage tracing. Our study identifies a novel cell type corresponding to the elusive follicle stem cell precursors and predicts sub-types of known cell types. Altogether, we reveal a previously unanticipated complexity of the developing ovary, and provide a comprehensive resource for the systematic analysis of ovary morphogenesis.

developmental biology↗