Transcriptional Elongation-Associated RNA Processing Errors in Induced Cellular Growth Arrest

Area of Science:

• Molecular Biology
• Gene Expression Regulation
• Cellular Senescence

Background:

• Transcription elongation factors are crucial for gene expression post-initiation by RNA polymerase II (RNAPII).
• Distinct roles of factors like NELF, SPT6, and Elongin A (ELOA) in transcription and RNA processing are not fully understood.
• The interplay between transcription elongation and pre-mRNA processing in cellular senescence remains an active area of research.

Purpose of the Study:

• To investigate the regulatory intersection of transcription elongation control and pre-mRNA processing.
• To elucidate the role of Elongin A (ELOA) in NELF and SPT6 depletion-induced phenotypes.
• To explore the connection between transcription elongation, senescence, and aging.

Main Methods:

• Utilized auxin-inducible degron systems for acute depletion of transcription elongation factors.
• Integrated long- and short-read RNA-sequencing for single-molecule resolution of transcript isoform usage.
• Performed genetic suppressor screens and analyzed RNAPII occupancy at transcription end sites (TES).

Main Results:

• Identified elongation factor-specific RNA processing regulons, including a senescence-associated regulon shared by NELF and SPT6.
• Demonstrated that NELF or SPT6 depletion leads to reversible growth arrest and upregulation of senescence genes (CDKN1A, CCN2).
• Showed that Elongin A (ELOA) loss suppresses NELF/SPT6 depletion phenotypes and opposes NELF/SPT6 effects on RNAPII processivity.

Conclusions:

• Established novel ELOA-dependent mechanisms regulating transcription maturation and pre-mRNA processing.
• Linked transcription elongation control by NELF, SPT6, and ELOA to cellular senescence and aging.
• ELOA genetic loss confers a growth advantage to aging human fibroblasts, highlighting its role in aging processes.