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During amphibian oogenesis, certain classes of mRNA are accumulated to specific cellular locations. One of these mRNAs, VG1, is found to accumulate at the so-called vegetal pole of the oocyte. In contrast, many mRNAs remain generally distributed throughout the oocyte's cytoplasm, and the GD mRNA provides a good example of such a distribution. Drugs that induce microtubule depolymerization inhibit the translocation of VG1 mRNA to the vegetal pole. Which mechanism is most likely used by the oocyte to localize VG1?

User Rofls
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The process of genetic material, in the form of RNAs in the amphibian oocyte is a pretty complex one. Essentially, during the process of oocyte formation and maturation, different RNAs, especially of maternal origin, become essential for the correct distribution of RNAs along the animal and vegetal axis, which will be central in determining the way that the different layers; endoderm, ectoderm and mesoderm, will develop and how characteristics in the embryo, once the oocyte is fertilized, will express.

Generally speaking, and according to research done, particularly mRNAs are originally produced and spread out throughout the cytoplasm, but once maturation begins, these mRNAs, at least some of them, will have to be distributed, or localized to their intended regions within the cell, so that they may express their genes correctly. One such mRNA that has to be localized specifically within the vegetal pole, is Vg1. And what research has shown is that the role of microfilaments and microtubules in this process is vital, as it is thanks to these cytoskeletal elements that Vg1 will be distributed to its rightful place by the start of stage IV and reach its peak at stage VI of oogenesis.

But how, during oogenesis, does Vg1 attach to the microfilaments and microtubules of the cytoskeleton to be able to move appropriately to its correct end depends entirely on the formation of a cis-acting sequence on the 5´ of the 3´ UTR. This sequence will be then responsible for permitting localization of Vg1 and its movement towars the vegetal end pole and not the animal one.

User Aksana
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