Transcriptional repression across mitosis: mechanisms and functions

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Gene expression relies on RNA polymerase (RNA Pol) enzymes, with RNA Pol II transcribing protein-coding genes in eukaryotes.
• Transcription is regulated by numerous factors influencing chromatin accessibility and DNA repair, with cell cycle stage critically impacting RNA Pol II activity.
• Mitosis poses a significant challenge, causing massive transcriptional inhibition and dissociation of the transcription machinery, thereby compromising cellular memory and identity.

Approach:

• This review evaluates the current understanding of transcriptional repression during mitosis.
• It focuses on the molecular mechanisms underlying this repression.
• The review also examines the functional significance of general repression and the transmission of the transcriptional machinery to daughter cells.

Key Points:

• Mitotic entry leads to widespread inhibition of RNA Pol II transcription and dissociation of transcription factors from chromatin.
• This temporary shutdown of transcription impacts the maintenance of cellular identity and epigenetic memory.
• Upon mitotic exit, transcription rapidly resumes, guiding cell fate and daughter cell progression.

Conclusions:

• Understanding the molecular mechanisms of mitotic transcriptional repression is crucial.
• The inheritance of the transcriptional machinery across mitosis is vital for cellular identity.
• Errors in this inheritance may contribute to stem cell aging.