The Nrd1-Nab3-Sen1 transcription termination complex from a structural perspective.

Area of Science:

• Molecular Biology
• Structural Biology
• Biophysics

Background:

• Transcription regulation is vital for cellular activity, with RNA Polymerase II controlling gene expression.
• Yeast RNA Pol II employs distinct termination pathways: poly(A)-dependent for mRNA and the Nrd1/Nab3/Sen1 (NNS) pathway for non-coding RNAs.
• The NNS pathway targets include small nucleolar RNAs (snoRNAs) and cryptic unstable transcripts (CUTs).

Approach:

• This review synthesizes current knowledge on the structural biology and biophysics of Nrd1, Nab3, and Sen1.
• Focuses on domain structures, interactions with peptide and RNA motifs, and heterodimerization of NNS components.
• Integrates structural data into the NNS transcription termination mechanism.

Key Points:

• The NNS complex, comprising Nrd1, Nab3, and Sen1, is essential for specific non-coding RNA termination in Saccharomyces cerevisiae.
• Structural and biophysical studies reveal detailed insights into the domain organization and interaction capabilities of NNS proteins.
• Understanding NNS component interactions with RNA and other proteins is key to elucidating the termination mechanism.

Conclusions:

• Structural and biophysical characterization of NNS components provides a foundation for understanding their role in transcription termination.
• Further research into the NNS pathway may uncover evolutionary insights into RNA processing and gene regulation.
• This review consolidates current understanding and points to future directions in NNS pathway research.