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Amran, A.

Publications and source records attributed to Amran, A..

3 recordsLinked to original sources

Patched regulates cell cycle and tissue architecture in C. elegans gonad

Hedgehog (Hh) signaling is essential for embryonic development and tissue homeostasis in several organisms. However, Caenorhabditis elegans lacks canonical Hh signaling due to the absence of key components, such as smoothened (SMO) and Hh ligands. Despite this, C. elegans retains Patched homologs, ptc-1 and ptc-3, which have specialized independent functions. Although ptc-1 is predominantly expressed in the gonads and ptc-3 in somatic tissues, we demonstrate that both genes are required to maintain germ cell populations and proper actin cytoskeletal architecture in the progenitor zone of the germline. Disruption of actin-encoding genes impairs germ cell cycle progression and reduces germ cell numbers, indicating that cytoskeletal integrity is critical for maintaining the germline. Furthermore, defects observed upon loss of Patched function are linked to disruptions in cholesterol metabolism. We show that the phenotypes observed in the gonads due to the loss of Patched function can be rescued by modulating dietary cholesterol. Together, our findings reveal a role for Patched receptors in regulating germline architecture and germ cell development through cholesterol-sensitive functions, offering insights into how metabolic cues influence the organization of complex tissues.

cell biology↗

A matrisome atlas of germ cell development

The extracellular matrix (matrisome) provides chemical and mechanical cues to control the structure and function of cells and tissues. Yet, comprehensive understanding of how matrisome factors individually and collectively control cell and tissue behavior in vivo is lacking. Here, we systematically investigate the function of 443 conserved matrisome-coding genes in controlling germ cell behavior within a complex tissue - the Caenorhabditis elegans germline. Using high-content imaging, 3D reconstruction and cell behavior analysis of >3500 germlines and >7 million germ cells, we identify specific matrisome factors that regulate germline structure, protein distribution, germ cell cycle and fate, apoptosis, and oocyte health. These findings reveal matrisome networks acting autonomously and non-autonomously to coordinate germ cell behavior, providing new avenues to study and manipulate cell fates.

cell biology↗

Notch-Directed Germ Cell Proliferation Is Mediated by Proteoglycan-Dependent Transcription

Notch receptors are essential membrane-bound regulators of cell proliferation and differentiation in metazoa. In the nematode Caenorhabditis elegans, correct expression of GLP-1 (germline proliferation-1), a germline-expressed Notch receptor, is important for germ cell maintenance. However, mechanisms that regulate GLP-1 expression are undefined. Here, we demonstrate that an AP-2 transcription factor (APTF-2) regulates GLP-1 expression through calcium-dependent binding to a conserved motif in the glp-1 promoter. Our data reveals that SDN-1 (syndecan-1), a transmembrane proteoglycan, regulates a TRP calcium channel in the soma to modulate the interaction between APTF-2 and glp-1 promoter - thus providing a potential communication nexus between the germline and its somatic environment to control germ cell fate decisions.

developmental biology↗