"MEX-5 is a novel, cytoplasmic protein that is localized through PAR activities to the anterior pole of the 1-cell stage embryo."

"MEX-5 is a novel, cytoplasmic protein that is localized through PAR activities to the anterior pole of the 1-cell stage embryo."

"MEX-5 localization is reciprocal to that of a group of posterior-localized proteins called germline proteins."

"Ectopic expression of MEX-5 is sufficient to inhibit the expression of germline proteins, suggesting that MEX-5 functions to inhibit anterior expression of the germline proteins."

"We provide evidence that two nearly identical genes, mex-5 and mex-6, link PAR asymmetry to those subsequent protein asymmetries."

"The kinase PAR-1 and the CCCH finger proteins MEX-5 and MEX-6 also function during the establishment phase in a feedback loop to regulate growth of the posterior domain."

"The kinase PAR-1 and the CCCH finger proteins MEX-5 and MEX-6 also function during the establishment phase in a feedback loop to regulate growth of the posterior domain."

"Using time-lapse microscopy and GFP fusions, we have analyzed the localization dynamics of PAR-2, PAR-6, MEX-5, MEX-6 and PIE-1 in wild-type and mutant embryos."

"Here we show that the TZF protein MEX-5, a primary anterior determinant, is an RNA-binding protein that recognizes linear RNA sequences with high affinity but low specificity."

"The minimal binding site is a tract of six or more uridines within a 9-13-nucleotide window."

"This sequence is remarkably abundant in the 3'-untranslated region of C. elegans transcripts"

"In contrast, human TZF homologs tristetraprolin and ERF-2 bind with high specificity to UUAUUUAUU elements."

"We show that mutation of a single amino acid in each MEX-5 zinc finger confers tristetraprolin-like specificity to this protein."

"We show that polo kinases, via their polo box domains, bind to and regulate the activity of two key polarity proteins, MEX-5 and MEX-6."

"We also show that MBK-2, a developmentally regulated DYRK2 kinase activated at meiosis II, primes T(186) for subsequent polo kinase-dependent phosphorylation."

"We identify an amino acid of MEX-5, T(186), essential for polo binding and show that T(186) is important for MEX-5 function in vivo."

"These polo kinases are asymmetrically localized along the anteroposterior axis of newly fertilized C. elegans embryos in a pattern identical to that of MEX-5 and MEX-6."

"This asymmetric localization of polo kinases depends on MEX-5 and MEX-6, as well as genes regulating MEX-5 and MEX-6 asymmetry."

"P granules are non-membrane-bound RNA-protein compartments that are involved in germline development in C. elegans. They are liquids that condense at one end of the embryo by localized phase separation"

"We reconstitute P granule-like droplets in vitro using a single protein PGL-3."

"we show that competition between PGL-3 and MEX-5 for mRNA can regulate the formation of PGL-3 droplets."

"In this model, MEX-5 influences the demixing of PGL-3 and mRNA by depleting the local free mRNA concentration."

"We conclude that gradients of polarity proteins can position RNP granules during development by using RNA competition to regulate local phase separation."

"*mex-5* encodes a cytoplasmic RNA-binding protein with tandem CCCH-type zinc finger domains that becomes enriched in the anterior cytoplasm of the one-cell *C. elegans* embryo and functions redundantly with *mex-6* to translate cortical PAR polarity into cytoplasmic asymmetries."

"a posterior-high PAR-1 kinase activity gradient and a broadly distributed phosphatase activity (PP2A/LET-92) drive phosphorylation-state interconversion between slow and fast diffusing MEX-5 species, yielding net anterior enrichment."

"PAR-1 phosphorylates MEX-5** in vitro and in vivo, with mapped sites including **S404** and **S458**; an S404A/S458A double mutant is not phosphorylated in vitro by activated PAR-1."

"MEX-5/6 are **RNA-binding polarity mediators** that act largely through **translational control** and regulated association with RNA-containing complexes. Their CCCH zinc fingers are required for normal mobility/asymmetry"

"MEX-5/6 bind the *zif-1* 3′UTR and promote its expression in somatic lineages by antagonizing POS-1 repression, enabling ZIF-1–dependent degradation of germline proteins such as PIE-1/POS-1/MEX-1 in somatic cells"

"MEX-5/6 are required for **anterior enrichment of PLK-1 and PLK-2**, and PLK-1/2 bind MEX-5/6 via their **polo-box domains**. Disrupting MEX-5–PLK binding impairs key MEX-5 activities (e.g., promoting PIE-1 degradation) without necessarily eliminating MEX-5 asymmetry, consistent with an adaptor/scaffold role rather than purely a localization effect."

"high anterior MEX-5 correlates with dissolution, while low posterior MEX-5 permits condensation/phase separation, providing a physical mechanism for segregating germ plasm components downstream of PAR polarity."