Pescadillo Is Essential for Nucleolar Assembly, Ribosome Biogenesis, and Mammalian Cell Proliferation

Alexandra Lerch-Gaggl,Jamil Haque,Jixuan Li,Gang Ning,Paula Traktman,Stephen A Duncan

doi:10.1074/jbc.m208338200

Alexandra Lerch-Gaggl, Jamil Haque + Show 4 more

Open Access

https://doi.org/10.1074/jbc.m208338200

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Abstract

Mutation of the zebrafish pescadillo gene blocks expansion of a number of tissues in the developing embryo, suggesting roles for its gene product in controlling cell proliferation. We report that levels of the pescadillo protein increase in rodent hepatocytes as they enter the cell cycle. Pescadillo protein localizes to distinct substructures of the interphase nucleus including nucleoli, the site of ribosome biogenesis. During mitosis pescadillo closely associates with the periphery of metaphase chromosomes and by late anaphase is associated with nucleolus-derived foci and prenucleolar bodies. Blastomeres in mouse embryos lacking pescadillo arrest at morula stages of development, the nucleoli fail to differentiate and accumulation of ribosomes is inhibited. We propose that in mammalian cells pescadillo is essential for ribosome biogenesis and nucleologenesis and that disruption to its function results in cell cycle arrest.

Highlights

Pescadillo was first identified in a genetic screen for mutations that affect embryonic development of the zebrafish Danio rerio (1, 2)
We propose that in mammalian cells pescadillo is essential for ribosome biogenesis and nucleologenesis and that disruption to its function results in cell cycle arrest
Pescadillo Protein Levels Are Increased in Proliferating Cells—If pescadillo has a role in controlling cell proliferation we believed it likely that it would be most highly expressed in proliferating tissues

Summary

EXPERIMENTAL PROCEDURES

Antibodies—Antibodies against pescadillo were generated commercially (Bethyl Laboratories Inc.) using peptides from the amino (N pep, EKKKYERGSAT, amino acids 5–15), middle (M pep, EGQAQAETKISEDTY, amino acids 251–265), and carboxyl regions of pescadillo (C pep, ALEQHRLEEKK, amino acids 494 –504). Immunoblotting—20 ␮g of protein from tissue or cell culture lysates were resolved on a 7% SDS-polyacrylamide gel and transferred to polyvinylidene difluoride membrane using a semi-dry transfer system (BioRad) in CAPS1 transfer buffer (10 mM CAPS, 10% methanol, pH 11.3). Partial Hepatectomy—6 – 8-week-old female CD-1 mice were anesthetized with tribromoethanol (Avertin) and subjected to two-thirds partial hepatectomy. During this procedure the left and right median and the left lateral lobes were removed.

Pescadillo and Mammalian Cell Proliferation

RESULTS

DISCUSSION