The Evolutionary Modifications of the AGS Protein's GoLoco Motif Facilitate Micromere Formation in the Sea Urchin Embryo

Alapfogalmak

The evolutionary modifications of the AGS protein's GoLoco motifs, particularly the GL1 motif, are critical for regulating its localization and function in facilitating micromere formation, a unique asymmetric cell division event in sea urchin embryos.

Kivonat

This study investigates how the evolutionary modifications of the Activator of G-protein Signaling (AGS) protein contribute to the emergence of micromeres, a unique cell lineage in sea urchin embryos.

The key highlights are:

• The N-terminal TPR domain of AGS is necessary to restrict its localization to the vegetal cortex, while the C-terminal GoLoco (GL) motifs, especially GL1, are critical for its cortical recruitment and function in micromere formation.
• Swapping the C-terminus of AGS with orthologs from other echinoderms reveals that the sequence and positioning of the GL motifs, particularly GL1, are important for AGS localization and function in asymmetric cell division.
• AGS directly recruits the conserved asymmetric cell division machinery, including Inscuteable, NuMA, and Dlg, as well as the fate determinant Vasa, to the vegetal cortex, facilitating micromere formation and downstream endomesoderm specification.
• The evolutionary modifications of a single polarity factor, AGS, appear to drive the diversity of asymmetric cell division programs among echinoderms, contributing to the developmental innovations within this phylum.

Statisztikák

The diameter ratio of the smallest cell (micromere-like cell) over the largest cell (macromere-like cell) was quantified for the embryos injected with the SpAGS mutants or EMTB-only (control).
The number of embryos forming micromeres was scored for each SpAGS mutant and EMTB-only (control).
The number of embryos developing to the pluteus stage was scored and normalized to that of Full AGS.
The number of embryos showing the localization of Insc, NuMA, and β-catenin in micromeres were scored and normalized to that of the Control MO.

Idézetek

"The evolutionary introduction of asymmetric cell division (ACD) into the developmental program facilitates the formation of a new cell type, contributing to developmental diversity and, eventually, to species diversification."
"We propose that the molecular evolution of a single polarity factor facilitates ACD diversity while preserving the core ACD machinery among echinoderms and beyond during evolution."
"SpAGS is a variable factor facilitating ACD diversity during species diversification."

Főbb Kivonatok

The evolutionary modifications of a GoLoco motif in the AGS protein facilitate micromere formation in the sea urchin embryo

by Emura,N., Wa... : www.biorxiv.org 07-02-2024

https://www.biorxiv.org/content/10.1101/2024.06.30.601440v1

Mélyebb kérdések

How might the evolutionary modifications of AGS in other phyla beyond echinoderms contribute to the diversity of asymmetric cell division programs and developmental innovations

The evolutionary modifications of AGS in other phyla beyond echinoderms could contribute to the diversity of asymmetric cell division programs and developmental innovations by influencing the localization and function of AGS in different species. As seen in the sea urchin embryo, AGS plays a crucial role in micromere formation and acts as a polarity factor that regulates ACD. In other phyla, AGS orthologs may have undergone specific changes in their C-terminus, affecting their interaction with G-proteins and other ACD factors. These modifications could lead to variations in the timing, location, and efficiency of ACD, resulting in diverse cell fate outcomes and developmental programs across different species. By fine-tuning the molecular interactions of AGS with other proteins and signaling pathways, organisms can adapt their ACD processes to meet specific developmental requirements, leading to evolutionary innovations in cell fate determination and tissue patterning.

What other polarity factors or signaling pathways might interact with AGS to fine-tune the asymmetric cell division process and cell fate specification in the sea urchin embryo

In addition to AGS, other polarity factors and signaling pathways may interact to fine-tune the asymmetric cell division process and cell fate specification in the sea urchin embryo. One such factor is Inscuteable (Insc), which is known to regulate the cortical localization of AGS orthologs in flies and mammals. Insc may work in conjunction with AGS to establish cell polarity and coordinate the orientation of the mitotic spindle during ACD. Additionally, proteins like NuMA and Dlg, which interact with AGS in other organisms, could play a role in spindle orientation and force generation in sea urchin embryos. Furthermore, Par3, a component of the PAR complex, may assist in localizing AGS and other polarity factors to the vegetal cortex, ensuring precise cell division and fate determination. By forming a complex network of interactions, these polarity factors and signaling pathways can synergistically regulate ACD and ensure the proper segregation of cell fate determinants during embryonic development.

Could the insights from this study on the evolutionary modifications of a single polarity factor be applied to engineer novel asymmetric cell division programs in other organisms or systems for biotechnological applications

The insights gained from studying the evolutionary modifications of a single polarity factor like AGS in the sea urchin embryo could be applied to engineer novel asymmetric cell division programs in other organisms or systems for biotechnological applications. By understanding how AGS interacts with other ACD factors and fate determinants to regulate cell division and lineage specification, researchers can potentially manipulate these interactions to control cell fate outcomes in a controlled manner. For example, by modulating the expression or activity of AGS and its interacting partners, scientists could design synthetic signaling pathways that drive specific cell fate decisions or tissue morphogenesis. This knowledge could be harnessed to create customized cell differentiation protocols for regenerative medicine, tissue engineering, or bioproduction applications. Additionally, insights into the molecular mechanisms of ACD diversity could inspire the development of novel tools and technologies for manipulating cell polarity and fate determination in various biological systems.