当前位置： SCI文献检索 > JOURNAL OF MOLECULAR BIOLOGY期刊下所有文献 > Assembly of the archaeal box C/D sRNP can occur via alternative pathways and requires temperature-facilitated sRNA remodeling.

Assembly of the archaeal box C/D sRNP can occur via alternative pathways and requires temperature-facilitated sRNA remodeling.

Abstract：

:Archaeal dual-guide box C/D small nucleolar RNA-like RNAs (sRNAs) bind three core proteins in sequential order at both terminal box C/D and internal C'/D' motifs to assemble two ribonuclear protein (RNP) complexes active in guiding nucleotide methylation. Experiments have investigated the process of box C/D sRNP assembly and the resultant changes in sRNA structure or "remodeling" as a consequence of sRNP core protein binding. Hierarchical assembly of the Methanocaldococcus jannaschii sR8 box C/D sRNP is a temperature-dependent process with binding of L7 and Nop56/58 core proteins to the sRNA requiring elevated temperature to facilitate necessary RNA structural dynamics. Circular dichroism (CD) spectroscopy and RNA thermal denaturation revealed an increased order and stability of sRNA folded structure as a result of L7 binding. Subsequent binding of the Nop56/58 and fibrillarin core proteins to the L7-sRNA complex further remodeled sRNA structure. Assessment of sR8 guide region accessibility using complementary RNA oligonucleotide probes revealed significant changes in guide region structure during sRNP assembly. A second dual-guide box C/D sRNA from M. jannaschii, sR6, also exhibited RNA remodeling during temperature-dependent sRNP assembly, although core protein binding was affected by sR6's distinct folded structure. Interestingly, the sR6 sRNP followed an alternative assembly pathway, with both guide regions being continuously exposed during sRNP assembly. Further experiments using sR8 mutants possessing alternative guide regions demonstrated that sRNA folded structure induced by specific guide sequences impacted the sRNP assembly pathway. Nevertheless, assembled sRNPs were active for sRNA-guided methylation independent of the pathway followed. Thus, RNA remodeling appears to be a common and requisite feature of archaeal dual-guide box C/D sRNP assembly and formation of the mature sRNP can follow different assembly pathways in generating catalytically active complexes.

journal_name

J Mol Biol

journal_title

Journal of molecular biology

authors

Gagnon KT,Zhang X,Agris PF,Maxwell ES

doi

10.1016/j.jmb.2006.07.091

subject

Has Abstract

pub_date

2006-10-06 00:00:00

pages

1025-42

issue

eissn

0022-2836

issn

1089-8638

pii

S0022-2836(06)00991-0

journal_volume

362

pub_type

杂志文章

在线工具

Assembly of the archaeal box C/D sRNP can occur via alternative pathways and requires temperature-facilitated sRNA remodeling.