Principles and roles of mRNA localization in animal development

Abstract

SummaryIntracellular targeting of mRNAs has long been recognized as a means to produce proteins locally, but has only recently emerged as a prevalent mechanism used by a wide variety of polarized cell types. Localization of mRNA molecules within the cytoplasm provides a basis for cell polarization, thus underlying developmental processes such as asymmetric cell division, cell migration, neuronal maturation and embryonic patterning. In this review, we describe and discuss recent advances in our understanding of both the regulation and functions of RNA localization during animal development.Key words: RNA localization, RNA transport, Local translation, Cell polarity, Post-transcriptional gene regulation Introduction Establishment of cell polarity is crucial for the execution of developmental programmes governing key processes, including specification of cell fates, individual or collective cell movements and specialization of somatic cell types. Cell polarization depends on the asymmetric segregation of organelles and various molecules within the cell. Polarized accumulation of RNA molecules was first visualized nearly 30 years ago, when -actin mRNA was found to be asymmetrically localized within ascidian eggs and embryos (Jeffery et al., 1983). Following this, the discovery of the first localized maternal mRNAs in Xenopus (Rebagliati et al., 1985) and Drosophila oocytes (Frigerio et al., 1986;Berleth et al., 1988) provided evidence for the earlier proposal that localized RNA determinants could be responsible for early embryonic patterning (Kandler-Singer and Kalthoff, 1976). mRNAs were soon found to be asymmetrically distributed within differentiated somatic cells, such as fibroblasts (Lawrence and Singer, 1986), oligodendrocytes (Trapp et al., 1987) and neurons (Garner et al., 1988), and to colocalize with their encoded proteins, establishing intracellular transport of mRNAs as a potential mechanism used to target the production of selected proteins to discrete sites.Significant improvements in RNA detection methods led to the identification of a growing number of localized mRNAs. Still, in the early 2000s, the set of described targeted mRNAs was limited to ~100 (reviewed by Bashirullah et al., 1998;Palacios and St Johnston, 2001) and the process of mRNA localization was thought to be restricted to specific cell types. However, recent genome-wide analyses (see Table 1) have changed this view dramatically, and strongly suggest that subcellular targeting of mRNAs is a prevalent mechanism used by polarized cells to establish functionally distinct compartments (Fig. 1). Particularly striking was the discovery that >70% of the 2314 expressed transcripts analysed in a highresolution in situ hybridization screen were subcellularly localized in Drosophila embryos (Lécuyer et al., 2007). Moreover, hundreds to thousands of mRNAs have been detected in cellular compartments as diverse as the mitotic apparatus (Blower et al., 2007;Sharp et al., 2011), pseudopodia (Mili et al., 2008), dendrites (Moccia et al., 2003;Poon et a...

YTHDF3 facilitates translation and decay of N6-methyladenosine-modified RNA

“…The potential functions of YTHDF3 in RNA transport and delivery in neuronal or related systems merit further studies. mRNA delivery and localization are also important in processes such as cell differentiation and animal development [32]. YTHDF3 has been reported to be upregulated by p63 in skin development and differentiation [33], and its transcript is m 6 A-methylated in ZFP217-mediated pluripotency and reprogramming regulation [34].…”

Transcription factors Mix1 and VegT, relocalization of vegt mRNA, and conserved endoderm and dorsal specification in frogs

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A stem–loop structure directsoskarmRNA to microtubule minus ends

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