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General Comment |
The intracellular localization of mRNA, a common mechanism for targeting
proteins to specific regions of the cell, probably occurs in most if not all
polarized cell types. Many of the best characterized localized mRNAs are found
in oocytes and early embryos, where they function as localized determinants
that control axis formation and the development of the germline.
Bullock SL, et al 2001 reported conserved signals and machinery for RNA transport in Drosophila
oogenesis and embryogenesis.
Localization of cytoplasmic messenger RNA transcripts is widely used to target
proteins within cells. For many transcripts, localization depends on
cis-acting elements within the transcripts and on microtubule-based motors;
however, little is known about other components of the transport machinery or
how these components recognize specific RNA cargoes. The authors show that in
Drosophila the same machinery and RNA signals drive specific accumulation of
maternal RNAs in the early oocyte and apical transcript localization in
blastoderm embryos. They demonstrate in vivo that Egalitarian (Egl) and Bicaudal D (BicD), maternal proteins required for oocyte determination, are selectively
recruited by, and co-transported with, localizing transcripts in blastoderm
embryos, and that interfering with the activities of Egl and BicD blocks
apical localization. It was proposed that Egl and BicD are core components of a
selective dynein motor complex that drives transcript localization in a
variety of tissues.
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