Nonhistone Nuclear Phosphoproteins
Lubomir S. Hnilica in Chromosomal Nonhistone Proteins, 2018
Newly synthesized nuclear messenger RNA(mRNA) precursors contain 100 to 200 adenylate residues at their 3′ termini. The polyadenylation is catalyzed by a chromatin-associated poly(A) polymerse.181,182 The precise function of the poly(A) tail is uncertain, although it has been suggested that it plays a role in the processing of the precursor to the smaller final product of messenger RNA. In any event, the activity of poly(A) polymerase appears to be regulated by phosphorylation. Rose and Jacob183 found that nuclear poly(A) polymerase from rat liver and Morris hepatoma 3924A contained 32P when it was isolated from nuclei that were previously incubated with [γ-32P]ATP (Figure 6).183 The hepatoma enzyme incorporated more than twice as much 32P than the liver enzyme. Purified poly (A) polymerase also became phosphorylated when incubated with exogenous protein kinase. Predominantly serine, and to a lesser extent threonine, became labeled by the kinase. More importantly, the enzyme activity was enhanced as much as tenfold by the phosphorylation (Figure 7).
Hormonal Regulation of Gene Transcription
Gerald M. Kolodny in Eukaryotic Gene Regulation, 2018
Munck and co-workers321,322 have defined the action of glucocorticoids on glucose transport in thymus cells by a series of steps: (1) an irreversible step in which C modifies glucocorticoid receptors; (2) an AcD-sensitive step, requiring at least 5 min of RNA synthesis; (3) a temperature-sensitive step, which influences the rapidity of the biological response; and (4) a cycloheximide-sensitive step. Using cordycepin, which in this case appears to block polyadenylation and not RNA synthesis, Young et al.323 have confirmed the essential features of this response. Chu and Edelman324 have also used cordycepin to show that in toad bladder, activation of sodium transport was mediated by RNA synthesis.
Introduction to Molecular Biology
Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman in Molecular Imaging in Oncology, 2008
The addition of poly (A) tails at the 3′ end of the transcript is called polyadenylation. This process takes place in the nucleus of the cell after transcription. After the polyadenylation signal has been transcribed, an endonuclease complex cleaves the mRNA chain and 50 to 250 adenosine residues are added to the free 3′ end at the cleavage site by the poly (A) polymerase. The polyadenylation process initially depends on the existence of the AAUAAA sequence for the first 10 nucleotides, but then is simply dependent on the preexisting poly (A) tail for the remaining 50 to 250 nucleotides. The poly (A) tails of eukaryotic mRNAs enhance their stability and facilitates their transport from the nucleus to the cytoplasm.
Evaluation of microRNA expression levels during the craving period of patients diagnosed with severe alcohol use disorder
Published in Journal of Substance Use, 2023
Kadir Aşçibaşi, Artuner Deveci, Berk Özyılmaz, Kadri Murat Erdoğan, Elif Çakıroğlu
MiRNA levels were determined using the Affymetrix GeneChip miRNA array version 4.0 (Thermo Fisher Scientific, Santa Clara, CA, USA), which measures expression levels of 2578 mature human miRNAs. The experiment was conducted in 5 stages in accordance with the manufacturer’s instructions. The isolated miRNA samples were prepared to obtain a solution of 8 µl with a concentration of 0.1–0.3 µg/µl. Polyadenylation was performed using ATP, enzymes, and buffers, followed by ligation with a biotin mixture and T4 DNA ligase enzyme. The samples were then hybridized to the array and incubated at 48°C for 16 hours in a hybridization oven. Finally, washing and staining were carried out using solutions at the wash station (GeneChip Fluidics Station 450 (Affymetrix, Santa Clara, CA, USA). The arrays were scanned using the GeneChip Scanner 3000 7 G (Affymetrix, Santa Clara, CA, USA), and the resulting data were prepared for analysis.
An overview of rational design of mRNA-based therapeutics and vaccines
Published in Expert Opinion on Drug Discovery, 2021
Kenneth K.W. To, William C.S. Cho
In eukaryotic cells, the mRNA poly(A) tail recruits the poly(A)-binding protein and subsequently the eIF4G translation initiation complex to mediate translation [78]. For IVT mRNA used for mRNA therapeutics, the poly(A) tail is either encoded in the DNA template or added enzymatically to the mRNA after the in vitro transcription procedure as a separate step. DNA template-encoded poly(A) has the advantage of producing defined and reproducible poly(A) length [79]. In contrast, enzymatic post-transcriptional polyadenylation of mRNA could produce transcripts with different poly(A) lengths and therefore may not meet regulatory requirements [80]. Enzymatic polyadenylation of mRNA has to be performed under alkaline conditions. Since mRNA is susceptible to alkaline hydrolysis, the enzymatic polyadenylation method is known to produce mRNA of inferior quality, especially with longer transcripts (>3 kb) [81].
First Report of the 3'-Untranslated Region +1506 (A>C) [NM_000518.5: c.*32A>C] mutation on the β-Globin Gene in the Indian Population
Published in Hemoglobin, 2021
Aditi Sen, Venu Seenappa, Prantar Chakrabarti, Tuphan Kanti Dolai
The adenylate uridylate (AU-rich) elements (AREs) are the most common regulatory elements in the 3′-UTR responsible for mRNA (de)stabilization and alternative pre-mRNA processing. A basic motif in AREs is represented by the pentamer ‘AUUUA’ that occurs in variable-length repetitions in the regions rich for uracil and interspersed with adenine. Usually, they encompass the facilitation of the deadenylation process resulting in the accelerated shortening of polyadenylation (polyA) tail, which is crucial for mRNA stability [5]. Therefore, a mutation in this region might be involved in the reduction of β-globin chain production. Here, we report a very rare mutation located in the first AU motif of 3′-UTR of the β-globin gene for the first time in India during mutation screening for prenatal diagnosis (PND) of an at-risk couple, and attempt to elucidate the resulting phenotype.
Related Knowledge Centers
- Adenine
- Adenosine Monophosphate
- Bacteria
- Directionality
- Eukaryote
- Gene Expression
- Messenger Rna
- Messenger Rna
- Translation
- Transcription
- Gene