Work

Distinct genome protective vs. ribosome synthetic functions of the paralogous nucleolar proteins nucleostemin and GNL3L

Year: 2014

Type: article

Abstract: The mammalian nucleolar proteins nucleostemin and GNL3-like (GNL3L) are encoded by paralogous genes that arose from an ancestral invertebrate gene, GNL3. Invertebrate GNL3 has been implicated in ribosome biosynthesis, as has its mammalian descendent, GNL3L. The paralogous mammalian nucleostemin protein has, instead, been implicated in cell renewal. Here, we found that depletion of nucleostemin in a human breast carcinoma cell line triggers prompt and significant DNA damage in S-phase cells without perturbing the initial step of ribosomal (r)RNA synthesis and only mildly affects the total ribosome production. By contrast, GNL3L depletion markedly impairs ribosome production without inducing appreciable DNA damage. These results indicate that, during vertebrate evolution, GNL3L retained the role of the ancestral gene in ribosome biosynthesis, whereas the paralogous nucleostemin acquired a novel genome-protective function. Our results provide a coherent explanation for what had seemed to be contradictory findings about the functions of the invertebrate versus vertebrate genes and are suggestive of how the nucleolus was fine-tuned for a role in genome protection and cell-cycle control as the vertebrates evolved.

Source: Journal of Cell Science

DOI: 10.1242/jcs.143842

Authors: Tao Lin, Lingjun Meng, Tsung-Chin Lin, Laura J. Wu, Thoru Pederson, Robert Y. L. Tsai

Institutions: Texas A&M Health Science Center, University of Massachusetts Chan Medical School

Language: English

Topic: Nuclear Structure and Function

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: green

Funder: National Cancer Institute