Small Cajal body-specific RNA
Find the organelles involved Cajal nucleus in the biosynthesis of (snurps or snRNPs) nuclear ribonucleic particularly small (scaRNAs) small RNA and Cajal body-specific, it is a small class of nucleolar RNA (snoRNAs). (Pseudouridylation and methylation) ScaRNAs induced modification of U12 and U1, U2, U4, U5 RNA polymerase II transcription spliceosome RNA. ScaRNA U85 were identified initially. In terms composite material that can guide the 2′-O-methylation and pseudouridylation and is the H / ACA snoRNAs and box C / D box, which is different from the snoRNAs typical. There is a H / ACA snoRNA box scaRNAs, integration and C / D all, the distinction does not mean not to gain structural and functional changes from the (rRNA) snoRNAs target ribosomal RNA in the nucleolus scaRNAs most.
In molecular biology, and are involved in pseudouridylation of spliceosome RNA U2 If it is RNA, small nucleolar found in the body Cajal (known as ACA35 or scaRNA1 also) RNA 1 a small mosquito Haar body-specific believed. The scaRNA1, is encoded RNA is a functional gene product, but it is not translated into protein. Usually, containing ligand-binding motif or secondary structure, significant, RNA such molecules is involved in important biological processes in many cell. In particular, scaRNAs is a class of small nuclear RNA localization to guide changes in the U12 and U1, U2, U4, U5 RNA polymerase II RNA transcription spliceosome and Cajal body. The flexible structure pointed tail, is scaRNA1, it belongs to the H / ACA box class guide RNA as a prediction that saved the H / ACA-box motif, found combined with GAR1 protein. This is supposed to guide the pseudouridylation of U2 spliceosome RNA remaining U89.
Mechanism involved in the synthesis of site-specific nucleotide that is showy snRNA modification remains of long mystery. I found that recently, nucleolus contains a large number of the snoRNAs 2′-O-methylation of direct pseudouridylation of rRNAs. 2′-O-methylation guide snoRNAs is, “D and” 5 ‘end and C (RUGAUGA) 3′-terminal D as well (CUGA) cans, an incomplete copy of the interior of these elements is called a C holding a box of wear. Use the fold structure of consensus’ hairpin hinge hairpin tail in pseudouridylation of. SnoRNAs are included in order to select the methylation sequence of site right in front of the box D or D “form snoRNA of 10-21 BPS spiral rRNAs saved the ACA box and (ANANNA) to “H. They have the recognition motif of rRNA between the two countries to form a helix and two short sequences of ribosome to the substrate before and after uridine. H / ACA motif and box C / D stored, such as accumulation of the nucleolus and the same processing snoRNAs which play an important role in snoRNA led RNA modification reaction. By binding to snoRNP particular protein, H / ACA box and C / D to achieve these jobs. So far, box H / ACA snoRNA Related four proteins have been identified (Snu13p fibrillarin, Nop56p, and Nop58p) 4 Box C / D. Perhaps, fibrillarin, and catalyst is a pseudouridine synthase Jisuke phosphorus box H / ACA snoRNPs and box C / D snoRNA guide 2′-O-methylation reaction.
8 Recent evidence – the synthesis of three pseudouridines RNA polymerase and 2′-O-methyl nucleotides, held at the nucleolus is U6 spliceosome snRNA’s (Paul) III-synthesis, it and box C / D I suggest that is directed to the H / ACA snoRNAs. In the U6 snRNA transcribed by the nucleoplasm, is conveyed to the nucleolus to undergo snoRNA-mediated modifications. The following is known about the U5 snRNA and U1, U2, U4 political situation II-transcription. nucleoplasmic After synthesis, RNA, these are transported to the cytoplasm to receive the formation of 3 ‘end and methylated caps associated with the Sm proteins seven. They are newly assembled snRNPs to the accumulation re-enter the nucleoplasm between chromatin granule cluster. However, nuclear power these agencies raise biosynthesis of snRNPs, the possibility that may have a function in storage or buying and selling, the proportion of snRNPs is temporarily under certain conditions in the nucleus and Cajal body are accumulated.