Rrp14 controls rRNA transcription via facilitating the translocation of Pol5 into the nucleolus

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Rrp14 is a conserved protein essential for rRNA processing and ribosomal biogenesis.
• In *Schizosaccharomyces pombe*, the *rrp14* gene is composed of two parts, *SPAC8C9.10 c* (*rrp14*) and *SPBC947.07* (*rrp1402*).
• While the *SPAC8C9.10 c* gene is not essential for survival, its deletion leads to impaired cell growth and reduced rRNA transcription.

Purpose of the Study:

• To identify proteins interacting with Rrp14.
• To elucidate the role of Rrp14 in nucleolar translocation of interacting proteins.
• To understand the mechanism by which Rrp14 influences rRNA transcription.

Main Methods:

• Protein interaction studies to identify Rrp14 binding partners.
• Pil1 co-tethering assay to assess nucleolus translocation.
• Gene deletion studies to evaluate the impact of Rrp14 and its motifs on cellular processes.

Main Results:

• A novel protein, Pol5, was identified to physically interact with Rrp14.
• Rrp14 facilitates the nucleolus translocation of Pol5, mediated by the 7-RINAWN-12 motif.
• Deletion of the 7-RINAWN-12 motif in Rrp14 disrupts Pol5 translocation and affects rRNA transcription.

Conclusions:

• Rrp14 plays a critical role in regulating rRNA transcription by mediating the nucleolus translocation of Pol5.
• The 7-RINAWN-12 motif of Rrp14 is essential for its interaction with Pol5 and subsequent regulation of rRNA synthesis.
• These findings provide new insights into the intricate mechanisms of ribosomal biogenesis and gene expression regulation in *S. pombe*.