Regulation of mRNA homeostasis by Poly(A) binding proteins

Descripción del proyecto

Investigación de las PABPC en la regulación del ARN y la homeostasis

El ARN es fundamental para la vida. Las células mantienen la concentración de ARN (homeostasis del ARN) equilibrando su síntesis y degradación. Un mecanismo de retroalimentación coordina los niveles de ARN mensajero (ARNm) a través de un «sensor» que comunica la concentración de ARNm a los controles de transcripción y degradación. Las proteínas citoplasmáticas de unión a poli(A) (PABPC) se unen a los ARNm para regular su estabilidad y traducción, pero aún no se conoce del todo su función en el mantenimiento de la homeostasis del ARN en condiciones fisiológicas. En el proyecto RNAhome, que cuenta con el apoyo de las acciones Marie Skłodowska-Curie, se combinará la titulación de PABPC, el marcaje metabólico y técnicas de imagenología simultánea para analizar la dinámica del ARN en respuesta a la variación de la concentración y localización de PABPC. El objetivo es descubrir los mecanismos básicos que regulan la homeostasis del ARN, así como principios generales de la regulación génica.

Objetivo

RNA is a biomolecule central to all life forms, and cells regulate RNA production and degradation rates to maintain stable RNA concentrations (RNA homeostasis) through a largely unexplored mechanism. Increasing evidence indicates that a feedback mechanism coordinates mRNA synthesis and degradation, allowing cells to buffer mRNA concentration. For the coordination of these processes, I hypothesise the existence of a “sensor” that “measures” mRNA concentration and conveys this information to the transcription and/or degradation machinery, establishing a coordinated response.

Cytoplasmic Poly(A)-binding proteins (PABPCs) are highly conserved across eukaryotes, and specifically bind to polyadenylated mRNAs, regulating their stability, translation, and degradation. Several properties of PABPCs, such as nuclear shuttling and transcription inhibition in response to viral infection, make them ideal candidates as mRNA sensors, yet it is unclear whether they control mRNA homeostasis in physiological conditions.

RNAhome will characterise the role of PABPCs in mRNA buffering and homeostasis using a systemic approach. I will conduct PABPC titration, followed by metabolic labelling and multiplexed imaging, to analyse RNA dynamics in response to varying PABPC expression and localisation. I will use my extensive expertise in nanoinjection to introduce mRNA into live cells and assess if PABPCs can directly sense mRNA levels and modulate transcription/turnover accordingly. Finally, I will use SLAMseq to measure genome-wide RNA dynamics with transcript-level resolution, establishing the impact of PABPC expression on mRNA dynamics.

RNAhome is a prime example of interdisciplinary science, combining the researcher’s expertise in bio-nanotechnology and physical sciences with RNA dynamics knowledge of the host group, and world-class facilities of the host organisation to unravel the fundamental mechanisms governing RNA homeostasis and drive innovation in RNA-based technologies.