In:
eLife, eLife Sciences Publications, Ltd, Vol. 5 ( 2016-11-23)
Abstract:
Cells and organisms survive and thrive in large part due to the activities of thousands of proteins. The instructions for making these proteins are found in the DNA sequences of genes. However, these genes also tend to contain large sections called introns that do not encode protein. To make a protein, the gene’s full sequence is first copied to a temporary molecule called pre-messenger RNA (pre-mRNA for short). The introns are then removed from the pre-mRNA in a process known as splicing in the cell nucleus, during which the remaining regions of the molecule, called exons, are joined together to form a mature mRNA molecule. This mature mRNA can then move out of the cell nucleus and be used as a template to build proteins around the cell. Intriguingly, splicing of the pre-mRNAs in the nucleus affects how the mRNA is used to make proteins in the cytoplasm of the cell. This nucleus-cytoplasm connection is currently explained by the so-called exon junction complex, which is thought to attach to mature mRNAs at the junction between two exons and stay bound until the mRNA moves to the cytoplasm. Evidence suggests the exon junction complex affects how the mRNA is used to make protein, yet little is known about how it would do so. Choudhury, Singh et al. examined how exon junction complex proteins bind to newly made RNA in salivary gland cells of fruit flies and in cultured cells. Contrary to expectations, the three proteins thought to make the central part of the exon junction complex were found on different mRNAs and regardless of whether the mRNAs derived from genes with introns. Specifically, one of these proteins – eIF4AIII – can remain on the mRNA independently of the two other exon junction complex proteins or CWC22, a protein required for splicing. CWC22 is also thought to be required for the complex to be deposited precisely at exon junctions in human cells. Overall, it appears that our current understanding of the exon junction complex needs to be revised. The findings presented by Choudhury, Singh et al. predict alternative roles for these proteins, particularly eIF4AIII, which will be independent of any deposition of the exon junction complex.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.19881.001
DOI:
10.7554/eLife.19881.002
DOI:
10.7554/eLife.19881.003
DOI:
10.7554/eLife.19881.004
DOI:
10.7554/eLife.19881.005
DOI:
10.7554/eLife.19881.006
DOI:
10.7554/eLife.19881.007
DOI:
10.7554/eLife.19881.008
DOI:
10.7554/eLife.19881.009
DOI:
10.7554/eLife.19881.010
DOI:
10.7554/eLife.19881.011
DOI:
10.7554/eLife.19881.012
DOI:
10.7554/eLife.19881.013
DOI:
10.7554/eLife.19881.014
DOI:
10.7554/eLife.19881.015
DOI:
10.7554/eLife.19881.016
DOI:
10.7554/eLife.19881.017
DOI:
10.7554/eLife.19881.018
DOI:
10.7554/eLife.19881.019
DOI:
10.7554/eLife.19881.020
DOI:
10.7554/eLife.19881.023
DOI:
10.7554/eLife.19881.024
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2016
detail.hit.zdb_id:
2687154-3
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