@article{e0484dd98f2f468f9dd3a5e06e2695ed,
title = "Ribosome biogenesis factors working with a nuclear envelope sun domain protein new players in the solar system",
abstract = "The nucleolus, the most prominent structure observed in the nucleus, is often called a {"}ribosome factory.{"} Cells spend an enormous fraction of their resources to achieve the mass-production of ribosomes required by rapid growth. On the other hand, ribosome biogenesis is also tightly controlled, and must be coordinated with other cellular processes. Ribosomal proteins and ribosome biogenesis factors are attractive candidates for this link. Recent results suggest that some of them have functions beyond ribosome biogenesis. Here we review recent progress on ribosome biogenesis factors, Ebp2 and Rrs1, in yeast Saccharomyces cerevisiae. In this organism, Ebp2 and Rrs1 are found in the nucleolus and at the nuclear periphery. At the nuclear envelope, these proteins interact with a membrane-spanning SUN domain protein, Mps3, and play roles in telomere clustering and silencing along with the silent information regulator Sir4. We propose that a protein complex consisting Ebp2, Rrs1 and Mps3 is involved in a wide range of activities at the nuclear envelope.",
keywords = "DNA damage, Mps3, Nuclear envelope, Nucleolus, Ribosome biogenesis, SUN protein, Silencing, Sir4, Telomere",
author = "Chihiro Horigome and Keiko Mizuta",
note = "Funding Information: biogenesis with cell proliferation. from the nuclear envelope in higher as telomere maintenance. Since the SUN While perinuclear localizations of EBP2 eukaryotes, several studies revealed the proteins impact a wide range of activities and RRS1 have not been reported to date existence of the structural links between at the nuclear envelope directly or except for budding yeast, we predict the nuclear envelope and nucleoli. indirectly, the understanding of the that the non-ribosomal functions of these Transmission electron microscopy (TEM) relationship between SUN proteins and proteins (which take place at the nuclear analysis of the ribonucleoprotein-contain-Ebp2/Rrs1 is likely to shed light on envelope in yeasts) are conserved in ing nuclear matrix fraction of HeLa cells, the true nature of genome organization. mammals and other species. As mentioned which includes EBP2 and BXDC1, Further studies will examine whether the above, the yeast two-hybrid screen for revealed the existence of RNase-sensitive nucelolar-and the perinuclear-Ebp2 and S. pombe SUN protein Sad1 identified fibers that extend throughout the nucleus, Rrs1 functions are related. only two nucleolar proteins, the S. pombe forming continuous association between Ebp2 and Rrs1.18 Therefore, it seems that nucleoli and the nuclear lamina.47 Given the interaction of perinuclear Ebp2 and that the shape of the extracted nucleus We regret the omission of many important Rrs1 with the unique SUN domain was sensitive to RNase, it was long references due to space constraint. We protein is conserved in fission yeast, proposed that RNA would be an import-thank Susan M. Gasser for support and although the role of this interaction has ant structural component of the nucleus. critical reading. This work was supported not been studied in S pombe. Human Alternative links may also exist; in the by grants from the Japanese Ministry EBP2 and RRS1 are found associated with germinal vesicle of Xenopus oocytes MEXT and JSPS. C.H. was financially condensed chromosomes in mitosis.39,41,42 bundles of actin extend from nucleoli to supported by JSPS Research Fellowship Intriguingly, SUN proteins also bind to the nuclear envelope,48,49 and lamin B1 for Young Scientists and Marie Curie the peripheral edges of condensed human appears to form an external scaffold for International Incoming Fellowship.",
year = "2012",
doi = "10.4161/nucl.18930",
language = "English",
volume = "3",
pages = "22--28",
journal = "Nucleus",
issn = "0115-2300",
publisher = "Landes Bioscience",
number = "1",
}