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SARS-CoV-2 Morphology, Genomic Organisation and Lifecycle
Published in Srijan Goswami, Chiranjeeb Dey, COVID-19 and SARS-CoV-2, 2022
Srijan Goswami, Ushmita Gupta Bakshi
But if the translation process while proceeding through OFR1a frameshifts to a region of ORF1b, the resultant protein thus formed is pp1ab. Polyprotein 1ab is the hybrid of ORF1a and ORF1b. These polyproteins are further proteolyzed into numerous smaller proteins and play a critical role in viral replication and transcription. Proteins involved in replication are called replicase complex while the proteins involved in transcription are called transcriptase complex. All these proteins combine with viral genomic RNA (sense strand) and facilitate replication. When the +ssRNA of the coronavirus replicates, an antisense RNA is produced. The conversion of the sense RNA into antisense RNA is very much important for the lifecycle of the virus. The antisense RNA is important because:It can be replicated back to sense RNA, which is essentially the same thing that entered with the original virus during uncoating.This antisense RNA can be transcribed through a method called discontinuous transcription. Discontinuous transcription of antisense RNA generates a diverse range of mRNAs that can then be translated into different proteins.
Gene Therapy for Lung Cancer
Published in Kenneth L. Brigham, Gene Therapy for Diseases of the Lung, 2020
Choon Taek Lee, David P. Carbone
Several antisense approaches have been investigated. One approach is through the use of antisense oligonucleotides, in which the phosphodiester backbone is modified to methylphosphonate or phosphorothioate to reduce degradation by nucleases. These modified antisense oligonucleotides can enter tumor cells by endocytosis and form DNA-RNA duplexes with endogenous sense mRNA, inhibiting translation. Another approach to inactivating mRNA is via ribozymes. Ribozymes are essentially antisense oligonucleotides that contain RNase active sites. A ribozyme possessing this activity allows catalytic gene ablation by sequence-specific cleavage of the target transcript. A third approach is to use plasmids or viral vectors for transferring an open reading frame fragment of the desired gene oriented backwards (3' to 5') behind a powerful promoter, resulting in the production of an antisense RNA. Antisense RNA transcribed from these constructs form a RNA duplex with sense mRNA inhibiting translation (89).
Hair Follicle Keratins
Published in John P. Sundberg, Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
George E. Rogers, Barry C. Powell
It is fairly clear from the mouse transgenesis results so far obtained that the pursuance of the transgenic approach for the overexpression or the ablation of keratin genes should shed light on the relative importance of the different proteins and how they interact. The techniques of antisense RNA or homologous recombination for disrupting gene expression will be increasingly used. The application of either of these approaches to the problem of the function of trichohyalin by preventing the formation of this abundant protein in the IRS and medulla cells is an investigation of central importance.
Resolution of coronavirus disease 2019 (COVID-19)
Published in Expert Review of Anti-infective Therapy, 2020
Khaled Habas, Chioma Nganwuchu, Fanila Shahzad, Rajendran Gopalan, Mainul Haque, Sayeeda Rahman, Anwarul Azim Majumder, Talat Nasim
Antisense RNA therapies including antisense oligonucleotides (ASOs), small RNAs or long non-coding RNAs have been considered to specifically treat various disorders including viral diseases. Upon entering the ASOs inside the host cells, they bind to the RNA target, resulting the formation of double-stranded hetero-duplex, which is then cleaved by cellular RNase H1 [71] . Formivirsen (Vitravene) is the first FDA-approved ASO, which inhibits the expression of major immediate early region 2 of the cytomegalovirus [72]. The drug has been approved for the treatment of peripheral cytomegalovirus retinitis in patients with AIDS [73]. Antisense RNAs have been used in clinical trials in various disorders including cancers, myopathies and Huntington’s disease [74]. As antisense-based therapies have shown beneficial effects in other diseases and they are easy to design and cost-effective to manufacture compared with small molecules and antibodies, they may hold promise for rapid drug development for SARS-CoV infections [75].
Intraflagellar transport proteins are involved in thrombocyte filopodia formation and secretion
Published in Platelets, 2018
Uvaraj Radhakrishnan, Abdullah Alsrhani, Hemalatha Sundaramoorthi, Gauri Khandekar, Meghana Kashyap, Jannon L Fuchs, Brian D Perkins, Yoshihiro Omori, Pudur Jagadeeswaran
To test whether ift122 knockdown interferes with thrombocyte aggregation, we performed laser-induced arterial thrombosis assays on 5 dpf larvae generated from a new batch of embryos injected with either ift122 MO or control MO. In this assay, TTO was taken as a measure of thrombocyte aggregation. The TTOs were collected in a blinded fashion. We found TTOs of the ift122 morphants were significantly greater than the control MO injected embryos (Figure 2A). These prolonged TTOs suggested that IFT122 is involved in processes responsible for thrombocyte aggregation. To determine whether the knockdown is specific to ift122 and not due to non-specific targeting we synthesized ift122 RNA by transcribing an ift122 full-length cDNA template amplified by RT-PCR using primers of ift122 cDNA with a sense primer having a T7 polymerase promoter sequence. As a control, antisense RNA was also prepared. A mixture ift122 MO and either the sense ift122 RNA or antisense ift122 RNA was injected into single cell stage embryos, and the resulting 5 dpf larvae were subjected to laser thrombosis assay. The TTOs were collected in a blinded fashion. The results showed that there is a reduction of TTO in ift122 RNA injected subjects compared to controls injected with antisense ift122 RNA suggesting that ift122 RNA rescued the phenotype and, thus, confirming the results are specific to knockdown of ift122 (Figure 2B).
Regulatory mechanisms of exopolysaccharide synthesis and biofilm formation in Streptococcus mutans
Published in Journal of Oral Microbiology, 2023
Ting Zheng, Meiling Jing, Tao Gong, Jiangchuan Yan, Xiaowan Wang, Mai Xu, Xuedong Zhou, Jumei Zeng, Yuqing Li
Antisense RNA (AS RNA) refers to an RNA that inhibits the expression of related genes after complementing with mRNA [57]. Lei et al. detected an AS RNA named ASvicR upstream of the rnc gene in S. mutans, whose overexpression inhibits the transcription of vicR, gtfB, gtfC and gtfD, resulting in the decrease of the exopolysaccharides synthesis and biofilm formation [58,59]. Moreover, msRNA1657, a microRNA-size small RNA, binds to the 5′-UTR region of the vicR gene [59,60]. This suggests that ASvicR and msRNA1657 regulate gtfs transcription through the vicR gene. At present, the detailed mechanisms of small RNA affecting the biofilm formation of S. mutans is still not well-known.