QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Research Data Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Deng, Y. Articles by Gu, W. PubMed PubMed Citation Articles by Deng, Y. Articles by Gu, W. Social Bookmarking                   What's this?

Translation of ASH1 mRNA is repressed by Puf6p–Fun12p/eIF5B interaction and released by CK2 phosphorylation

¹ Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA; ² Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA

Translational repression during mRNA transport is essential for spatial restriction of protein production. In the yeast Saccharomyces cerevisae, silencing of ASH1 mRNA before it is localized to the bud cortex in late anaphase is critical for asymmetric segregation of Ash1p to the daughter cell nucleus. Puf6p, an ASH1 mRNA-binding protein, has been implicated in this process as a translational repressor, but the underlying mechanism is unknown. Here, we used yeast extract-based in vitro translation assays, which recapitulate translation and phosphorylation, to characterize the mechanism of Puf6p-mediated translational regulation. We report that Puf6p interferes with the conversion of the 48S complex to the 80S complex during initiation, and this repression by Puf6p is mediated through the general translation factor eIF5B (Fun12p in S. cerevisiae). Puf6p interacts with Fun12p via the PUF domain, and this interaction is RNA-dependent and essential for translational repression by Puf6p. This repression is relieved by phosphorylation of the N-terminal region of Puf6p mediated by protein kinase CK2 (casein kinase II). Inhibition of phosphorylation at Ser31, Ser34, and Ser35 of Puf6p increases its translational repression and results in ASH1 mRNA delocalization. Our results indicate that Puf6p suppresses the translation initiation of ASH1 mRNA via interaction with Fun12p during its transport, and this repression can be released by CK2 phosphorylation in the N-terminal region of Puf6p when the mRNA reaches the bud tip.

[Keywords: Translational regulation; RNA localization; RNA transport]]

Received December 19, 2007; revised version accepted February 12, 2008.

⁴ Corresponding authors.

E-MAIL rhsinger{at}aecom.yu.edu; FAX (718) 430-8697.

⁵ E-MAIL wgu{at}aecom.yu.edu; FAX (718) 430-8697.

Supplemental material is available at http://www.genesdev.org.

Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.1611308.

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?