The RNA ‐binding protein MARTA 2 regulates dendritic targeting of MAP 2 mRNA s in rat neurons

• Published in: Journal of neurochemistry Vol. 124; no. 5; pp. 670 - 684
• Main Authors: Zivraj, Krishna H., Rehbein, Monika, Ölschläger‐Schütt, Janin, Schob, Claudia, Falley, Katrin, Buck, Friedrich, Schweizer, Michaela, Schepis, Antonino, Kremmer, Elisabeth, Richter, Dietmar, Kreienkamp, Hans‐Jürgen, Kindler, Stefan
• Format: Journal Article
• Language: English
• Published: 01.03.2013
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/jnc.12079

Abstract Dendritic targeting of mRNA s encoding the microtubule‐associated protein 2 ( MAP 2) in neurons involves a cis ‐acting dendritic targeting element. Two rat brain proteins, MAP2‐RNA trans ‐acting protein ( MARTA )1 and MARTA 2, bind to the cis ‐element with both high affinity and specificity. In this study, affinity‐purified MARTA 2 was identified as orthologue of human far‐upstream element binding protein 3. In neurons, it resides in somatodendritic granules and dendritic spines and associates with MAP 2 mRNA s. Expression of a dominant‐negative variant of MARTA 2 disrupts dendritic targeting of endogenous MAP 2 mRNA s, while not noticeably altering the level and subcellular distribution of polyadenylated mRNA s as a whole. Finally, MAP 2 transcripts associate with the microtubule‐based motor KIF 5 and inhibition of KIF 5, but not cytoplasmic dynein function disrupts extrasomatic trafficking of MAP 2 mRNA granules. Thus, in neurons MARTA 2 appears to represent a key trans ‐acting factor involved in KIF 5‐mediated dendritic targeting of MAP 2 mRNA s.