High impact information on NOP7

• Yph1p levels decline as cells commit to exit the cell cycle, and levels vary depending on energy source [1].
• Yph1p, an ORC-interacting protein: potential links between cell proliferation control, DNA replication, and ribosome biogenesis [1].
• Yph1p may link cell proliferation control to DNA replication, ribosome biogenesis, and translation on polysomes [1].
• Yph1p is predominantly nucleolar and is required for 60S ribosomal subunit biogenesis and possibly for translation on polysomes [1].
• Proliferating cells depleted of Yph1p arrest in G(1) or G(2), with no cells in S phase, or significantly delay S phase progression after release from a hydroxyurea arrest [1].

Biological context of NOP7

• Two clones were identified encoding a segment of YPH1 (yeast pescadillo homolog), which is essential for cell cycle progression in yeast [2].
• Deletion analysis revealed that the catalytic domain of Yvh1p and the BRCT domain of Yph1p are sufficient for this interaction [2].

Anatomical context of NOP7

• The temperature-sensitive nop7-1 mutation or metabolic depletion of Nop7p results in a deficiency of 60S ribosomal subunits and accumulation of halfmer polyribosomes [3].

Regulatory relationships of NOP7

• We found that the multicopy of YPH1 not only suppressed slow growth but also decreased IME2 expression in the yvh1 disruptant [2].

Other interactions of NOP7

• Thus Nop7p, like Drs1p, is required for essential steps leading to synthesis of 60S ribosomal subunits [3].
• Nop7p is localized primarily in the nucleolus, where most steps in ribosome assembly occur [3].
• Ytm1, Nop7, and Erb1 form a complex necessary for maturation of yeast 66S preribosomes [4].
• However, Nop7 and Erb1 assemble into preribosomes prior to Ytm1 [4].
• Depletion of Nop7p leads to nuclear accumulation of pre-60S particles, indicating a defect in subunit export, and it interacts genetically with a tagged form of the ribosomal protein Rpl25p, consistent with a role in subunit assembly [5].

Analytical, diagnostic and therapeutic context of NOP7

• Immunoprecipitation of the origin recognition complex (ORC) from yeast extracts identified Yph1p, an essential protein containing a BRCT domain [1].

References