RNA transcription

Chương này trình bày đến người học về quá trình tổng hợp RNA. Quá trình tổng hợp RNA gồm có 4 bước, đó là: Gắn kết vào khuôn mẫu, khởi đầu chuỗi, kéo dài chuỗi, kết thúc chuỗi & giải phóng khuôn mẫu. Mời các bạn cùng tham khảo.

41p tieu_vu16 03-01-2019 50 3   Download

The plastid transcription kinase (PTK), a component of the major RNA polymerase complex from mustard chloroplasts, has been implicated in redox-mediated regulation of plastid gene expression. A cloning strategy to define the PTK gene(s) resulted in the isolation of a full-length cDNA for a protein with overall high homology with the a subunit of cytosolic casein kinase (CK2) that contained an N-terminal extension for a putative plastid transit peptide.

9p system191 01-06-2013 46 4   Download

We report the cloning and functional charaterization of the full-length cDNA and gene encoding a Toxoplasma gondii DNA repair enzyme designated TgDRE. The gene is composed of three exons separated by two introns of 780 and 630 bp, and encodes a protein with a predicted molecular mass of 49.6 kDa. The native TgDRE protein, with a molecular mass of 60 kDa, is only detected in the virulent tachyzoite stage of T. gondii. However, the transcript is present in both asexual parasite stages, virulent tachyzoite and avirulent encysted bradyzoite. ...

9p research12 01-06-2013 35 5   Download

The intrachloroplastic localization of post-transcriptional gene expression steps represents one key determinant for the regulation of chloroplast development. We have character-ized an RNA binding protein of 63kDa (RBP63) from Chlamydomonas reinhardtiichloroplasts, which cofraction-ates with stromal thylakoid membranes. Solubility proper-ties suggest that RBP63is a peripheral membrane protein.

8p research12 23-04-2013 34 3   Download

Minichromosomemaintenance (MCM) proteins are part of the replication licensing factor (RLF-M), which limits the initiationofDNAreplication to once per cell cycle.We have previously reported that higher order complexes of mam-malian pol II and general pol II transcription factors, referred to as pol II holoenzyme, also contain MCM pro-teins. In the present study we have analyzed in detail the interaction between MCM2 and pol II holoenzyme. N- and C- terminal deletions were introduced into epitope-tagged MCM2 and the truncated proteins were transiently expressed in 293 cells. ...

11p tumor12 22-04-2013 39 3   Download

The nonphotosynthetic mutant ofArabidopsis hcf152is impaired in the processing of the chloroplast polycistronic transcript, psbB-psbT-psbH-petB-petD, resulting in non-production of the essential photosynthetic cytochromeb6 f complex. The nucleus-encodedHCF152gene was identified to encode a pentatricopeptide repeat (PPR) protein com-posed primarily of 12 PPR motifs, similar to other proteins of this family that were identified in mutants defected in chloroplast gene expression.

12p tumor12 20-04-2013 32 2   Download

The transcription patterns of 64 linear double stranded DNA templates obtained with T7 RNA polymerase were investigated. These templates consisted of 17 nucleotide-long sequences under the control of the minimal bac-teriophage T7 promoter and represented all possible combinations of nucleotides at positions +8, +10 and +11.

8p tumor12 20-04-2013 33 5   Download

Cold shock proteins (CSPs) form a family of highly conserved bacterial proteins capable of single-stranded nucleic acid binding. They are suggested to act as RNA chaperones during cold shock inhibiting the formation of RNA secondary structures, which are unfavourable for transcription and translation.

12p fptmusic 12-04-2013 37 2   Download

PMAP-36 is a cathelicidin-derived host defence peptide originally deduced by a transcript from pig bone marrow RNA. The expression of the propep-tide in leukocytes, and the structure, antimicrobial activity, and mechanism of action of the mature peptide were investigated. The proform is stored as a dimeric precursor of 38 kDa formed by a dimerization site at its C-ter-minal cysteine residue; it is likely that the mature peptide is dimeric when released.

9p fptmusic 11-04-2013 50 2   Download

There is still a controversy over the mechanism of promoter DNA strand separation upon open transcription complex (RPo) formation by Escheri-chia coli RNA polymerase: is it a single or a stepwise process controlled by Mg 2+ ions and temperature? To resolve this question, the kinetics of pseudo-first-order oxidation of thymine residues by KMnO4 in the )11…+2 DNA region of RPo at thekPRpromoter was examined under single-hit conditions as a function of temperature (13–37
C) in the absence or presence of 10 mmMgCl2....

16p awards 06-04-2013 45 2   Download

The RNA recognition motif (RRM), also known as RNA-binding domain (RBD) or ribonucleoprotein domain (RNP) is one of the most abundant protein domains in eukaryotes. Based on the comparison of more than 40 structures including 15 complexes (RRM–RNA or RRM–protein), we reviewed the structure–function relationships of this domain. We identified and classified the different structural elements of the RRM that are import-ant for binding a multitude of RNA sequences and proteins.

14p awards 06-04-2013 42 2   Download

PKR is an interferon-induced serine-threonine protein kinase that plays an important role in the mediation of the antiviral and antiproliferative actions of interferons. PKR is present at low basal levels in cells and its expression is induced at the transcriptional level by interferons. PKR’s kin-ase activity stays latent until it binds to its activator. In the case of virally infected cells, double-stranded (ds) RNA serves as PKR’s activator.

15p awards 06-04-2013 31 2   Download

Messenger RNA trafficking, which provides a mechanism for local protein synthesis, is dependent on cis-acting sequences in the 3¢ untranslated regions (3¢UTRs) of the mRNAs concerned acting together withtrans-act-ing proteins. The C-MYC transcription factor is a proto-oncogene product involved in cell proliferation, differentiation and apoptosis. Localization of c-myc mRNA to the perinuclear cytoplasm and its association with the cytoskeleton is determined by a signal in the 3¢UTR.

0p awards 05-04-2013 41 4   Download

BacterialRNApolymerase (RNAP) is the central enzyme of gene expression that is responsible for the synthesis of all types of cellular RNAs. The process of transcription is accompanied by complex structural rearrangements of RNAP. Despite the recent progress in structural studies of RNAP, detailed mechanisms of conformational changes of RNAP that occur at different stages of transcription remain unknown.

11p awards 05-04-2013 42 2   Download

Loss of cannabinoid receptors (CB1) occurs prior to neuro-degeneration in Huntington’s disease (HD). The levels and distribution of CB1 RNA were equivalent in 3-week-old mice regardless of genotype demonstrating that the specific factors and appropriate chromatin structure that lead to the transcription ofCB1were present in the striatum of young R6/2 and R6/1 transgenic HD mice.

12p awards 05-04-2013 55 5   Download

RNA helicase A (RHA), a member of DNA and RNA helicase family containing ATPase activity, is involved in many steps of gene expression such as transcription and mRNA export. RHA has been reported to bind directly to the transcriptional coactivator, CREB-binding protein, and the tumor suppressor protein, BRCA1, and links them to RNAPolymerase II holoenzyme complex. Using yeast two-hybrid screening, we have identified RHA as an interacting molecule of the p65 subunit of nuclear factorjB(NF-jB).

11p awards 05-04-2013 31 4   Download

RNA polymerase II (RNAPII) requires a set of general transcription factors )TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH)to initiate transcription from a gene promoterin vitro. General transcription factors have been isolated from Saccharomyces cerevisiae,rat, human and Drosophila,and their corresponding cDNAs have been cloned. In this report, we describe a reconstitutedin vitro transcription system that consists of the following prepara-tions of factors from the yeastSchizosaccharomyces pombe: affinity-purified RNAPII, TFIIH, and recombinant TBP, TFIIB, TFIIE and TFIIF. ...

12p dell39 03-04-2013 62 3   Download

The C-terminal domain (CTD) of the largest subunit of RNA polymerase II plays critical roles in the initiation, elongation and processing of primary transcripts. These activities are at least partially regulated by the phosphory-lation of the CTDby three cyclin-dependent protein kinases (CDKs), namely CDK7, CDK8 and CDK9. In this study, we systematically compared the phosphorylation of differ-ent recombinant CTD substrates by recombinant CDK7/ CycH/MAT1, CDK8/CycCandCDK9/CycT1 kinases.We showed that CDK7, CDK8 and CDK9 produce different patterns of phosphorylation of the CTD. ...

11p dell39 03-04-2013 45 3   Download

Vascular endothelial growth factor (VEGF) is a key regu-lator of angiogenesis and post-transcriptional regulation plays a major role in VEGF expression. Both the 5¢-and 3¢-UTR are required for VEGF post-transcriptional regu-lation but factors binding to functional sequences within the 5¢-UTR have not been fully characterized. We report here the identification of complexes, binding to theVEGF mRNA 5¢-and3¢-UTR, that contain cold shock domain (CSD) and polypyrimidine tract binding (PTB) RNA binding proteins. ...

13p dell39 03-04-2013 42 5   Download

The human 2¢)5¢ oligoadenylate synthetases (OAS) form a conserved family of interferon-induced proteins consisting of four genes:OAS1, OAS2, OAS3and the 2¢)5¢ oligo-adenylate synthetase-like gene (OASL). When activated by double-strandedRNA,OAS1–3polymerizeATP into2¢)5¢-linkedoligoadenylates; 2¢)5¢-linkedoligoadenylates, in turn, activate a latent endoribonuclease that degrades viral and cellular RNAs. In contrast, while the p59 OASLprotein is highlyhomologous to theOAS family (45%identity), its 350 amino acid N-terminal domain lacks 2¢)5¢ oligoadenylate synthetase activity. ...

9p dell39 03-04-2013 43 5   Download