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Conservation of RNA chaperone activity of the human La-related proteins 4, 6 and 7.

Hussain RH, Zawawi M, Bayfield MA - Nucleic Acids Res. (2013)

Bottom Line: The La module has also been identified in several conserved families of La-related proteins (LARPs) that engage other RNAs, but their mode of RNA binding and function(s) are not well understood.Rather, the capacity of these to enhance pre-tRNA maturation is associated with RNA chaperone function, which we demonstrate to be a conserved activity for each hLARP in vitro.Our work reveals insight into the mechanisms by which La module containing proteins discriminate RNA targets and demonstrates that RNA chaperone activity is a conserved function across representative members of the La motif-containing superfamily.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada.

ABSTRACT
The La module is a conserved tandem arrangement of a La motif and RNA recognition motif whose function has been best characterized in genuine La proteins. The best-characterized substrates of La proteins are pre-tRNAs, and previous work using tRNA mediated suppression in Schizosaccharomyces pombe has demonstrated that yeast and human La enhance the maturation of these using two distinguishable activities: UUU-3'OH-dependent trailer binding/protection and a UUU-3'OH independent activity related to RNA chaperone function. The La module has also been identified in several conserved families of La-related proteins (LARPs) that engage other RNAs, but their mode of RNA binding and function(s) are not well understood. We demonstrate that the La modules of the human LARPs 4, 6 and 7 are also active in tRNA-mediated suppression, even in the absence of stable UUU-3'OH trailer protection. Rather, the capacity of these to enhance pre-tRNA maturation is associated with RNA chaperone function, which we demonstrate to be a conserved activity for each hLARP in vitro. Our work reveals insight into the mechanisms by which La module containing proteins discriminate RNA targets and demonstrates that RNA chaperone activity is a conserved function across representative members of the La motif-containing superfamily.

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Related in: MedlinePlus

tRNA mediated suppression by the human LARPs does not correlate with UUU-3′OH dependent 3′-end protection. Northern analysis for pre-tRNALysCUU (20,38) was performed to measure the capacity of the full-length and La modules of hLARP4, 6 and 7 to support the accumulation of pre-tRNA intermediates as has been previously shown for genuine human and yeast La. (A) probed using pre-tRNALysCUU intron complementary probe, which detects newly transcribed, leader and trailer containing pre-tRNA (top band), leader processed pre-tRNA (middle) and leader and trailer processed (bottom) pre-tRNA (20,38). Locations of regions of complementarity of probes on pre-tRNAs indicated by dashed lines. (B) same blot probed using pre-tRNALysCUU trailer complementary probe. (C) same blot probed for the U5 snRNA as a loading control.
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gkt649-F3: tRNA mediated suppression by the human LARPs does not correlate with UUU-3′OH dependent 3′-end protection. Northern analysis for pre-tRNALysCUU (20,38) was performed to measure the capacity of the full-length and La modules of hLARP4, 6 and 7 to support the accumulation of pre-tRNA intermediates as has been previously shown for genuine human and yeast La. (A) probed using pre-tRNALysCUU intron complementary probe, which detects newly transcribed, leader and trailer containing pre-tRNA (top band), leader processed pre-tRNA (middle) and leader and trailer processed (bottom) pre-tRNA (20,38). Locations of regions of complementarity of probes on pre-tRNAs indicated by dashed lines. (B) same blot probed using pre-tRNALysCUU trailer complementary probe. (C) same blot probed for the U5 snRNA as a loading control.

Mentions: ahLARP7 full-length (1–582): stable accumulation of leader processed but trailer containing pre-tRNA intermediate (see Figure 3 and text).


Conservation of RNA chaperone activity of the human La-related proteins 4, 6 and 7.

Hussain RH, Zawawi M, Bayfield MA - Nucleic Acids Res. (2013)

tRNA mediated suppression by the human LARPs does not correlate with UUU-3′OH dependent 3′-end protection. Northern analysis for pre-tRNALysCUU (20,38) was performed to measure the capacity of the full-length and La modules of hLARP4, 6 and 7 to support the accumulation of pre-tRNA intermediates as has been previously shown for genuine human and yeast La. (A) probed using pre-tRNALysCUU intron complementary probe, which detects newly transcribed, leader and trailer containing pre-tRNA (top band), leader processed pre-tRNA (middle) and leader and trailer processed (bottom) pre-tRNA (20,38). Locations of regions of complementarity of probes on pre-tRNAs indicated by dashed lines. (B) same blot probed using pre-tRNALysCUU trailer complementary probe. (C) same blot probed for the U5 snRNA as a loading control.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3794603&req=5

gkt649-F3: tRNA mediated suppression by the human LARPs does not correlate with UUU-3′OH dependent 3′-end protection. Northern analysis for pre-tRNALysCUU (20,38) was performed to measure the capacity of the full-length and La modules of hLARP4, 6 and 7 to support the accumulation of pre-tRNA intermediates as has been previously shown for genuine human and yeast La. (A) probed using pre-tRNALysCUU intron complementary probe, which detects newly transcribed, leader and trailer containing pre-tRNA (top band), leader processed pre-tRNA (middle) and leader and trailer processed (bottom) pre-tRNA (20,38). Locations of regions of complementarity of probes on pre-tRNAs indicated by dashed lines. (B) same blot probed using pre-tRNALysCUU trailer complementary probe. (C) same blot probed for the U5 snRNA as a loading control.
Mentions: ahLARP7 full-length (1–582): stable accumulation of leader processed but trailer containing pre-tRNA intermediate (see Figure 3 and text).

Bottom Line: The La module has also been identified in several conserved families of La-related proteins (LARPs) that engage other RNAs, but their mode of RNA binding and function(s) are not well understood.Rather, the capacity of these to enhance pre-tRNA maturation is associated with RNA chaperone function, which we demonstrate to be a conserved activity for each hLARP in vitro.Our work reveals insight into the mechanisms by which La module containing proteins discriminate RNA targets and demonstrates that RNA chaperone activity is a conserved function across representative members of the La motif-containing superfamily.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada.

ABSTRACT
The La module is a conserved tandem arrangement of a La motif and RNA recognition motif whose function has been best characterized in genuine La proteins. The best-characterized substrates of La proteins are pre-tRNAs, and previous work using tRNA mediated suppression in Schizosaccharomyces pombe has demonstrated that yeast and human La enhance the maturation of these using two distinguishable activities: UUU-3'OH-dependent trailer binding/protection and a UUU-3'OH independent activity related to RNA chaperone function. The La module has also been identified in several conserved families of La-related proteins (LARPs) that engage other RNAs, but their mode of RNA binding and function(s) are not well understood. We demonstrate that the La modules of the human LARPs 4, 6 and 7 are also active in tRNA-mediated suppression, even in the absence of stable UUU-3'OH trailer protection. Rather, the capacity of these to enhance pre-tRNA maturation is associated with RNA chaperone function, which we demonstrate to be a conserved activity for each hLARP in vitro. Our work reveals insight into the mechanisms by which La module containing proteins discriminate RNA targets and demonstrates that RNA chaperone activity is a conserved function across representative members of the La motif-containing superfamily.

Show MeSH
Related in: MedlinePlus