Orb-dependent polyadenylation contributes to PLP expression and centrosome scaffold assembly

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Centrosomes are critical microtubule-organizing centers essential for accurate cell division.
• Drosophila Pericentrin-like protein (PLP) organizes the pericentriolar material (PCM) scaffold for centrosome function.
• Post-transcriptional regulation of mRNA plays a vital role in controlling protein levels.

Purpose of the Study:

• To investigate the post-transcriptional regulation of Plp mRNA.
• To determine the role of the CPEB ortholog, Oo18 RNA-binding protein (Orb), in Plp mRNA regulation.
• To understand the impact of Orb-mediated PLP regulation on centrosome function and embryonic development.

Main Methods:

• Identification of conserved cytoplasmic polyadenylation element binding (CPEB) protein binding sites in the Plp 3'-untranslated region.
• Biochemical interaction assays between Orb and Plp mRNA.
• Analysis of PLP protein levels, centrosome localization, and PCM scaffolding in orb mutant embryos.
• Assessment of embryonic lethality and cell division defects in orb mutants.

Main Results:

• Orb directly interacts with Plp mRNA, promoting its polyadenylation and increasing PLP protein expression.
• Loss of orb function, but not orb2, leads to reduced PLP levels, impaired centrosome scaffolding, and genomic instability.
• Overexpression of PLP can rescue centrosome defects and cell division issues caused by orb depletion.
• Orb-mediated regulation of Plp mRNA is crucial for maintaining centrosome integrity and proper mitosis.

Conclusions:

• Orb functions as a key regulator of PLP expression through mRNA polyadenylation.
• Post-transcriptional control of centrosomal mRNAs like Plp is essential for centrosome function, genomic stability, and embryonic viability.
• This study highlights the importance of RNA-binding proteins in orchestrating complex cellular processes.