scholarly journals Transcription Strategy of Coronaviruses: Fusion of Non-Contiguous Sequences During mRNA Synthesis

Author(s):  
Willy Spaan ◽  
Hajo Delius ◽  
Mike A. Skinner ◽  
John Armstrong ◽  
Pete Rottier ◽  
...  
Keyword(s):  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Álvaro Figueroa ◽  
Antonio Brante ◽  
Leyla Cárdenas

AbstractThe polychaete Boccardia wellingtonensis is a poecilogonous species that produces different larval types. Females may lay Type I capsules, in which only planktotrophic larvae are present, or Type III capsules that contain planktotrophic and adelphophagic larvae as well as nurse eggs. While planktotrophic larvae do not feed during encapsulation, adelphophagic larvae develop by feeding on nurse eggs and on other larvae inside the capsules and hatch at the juvenile stage. Previous works have not found differences in the morphology between the two larval types; thus, the factors explaining contrasting feeding abilities in larvae of this species are still unknown. In this paper, we use a transcriptomic approach to study the cellular and genetic mechanisms underlying the different larval trophic modes of B. wellingtonensis. By using approximately 624 million high-quality reads, we assemble the de novo transcriptome with 133,314 contigs, coding 32,390 putative proteins. We identify 5221 genes that are up-regulated in larval stages compared to their expression in adult individuals. The genetic expression profile differed between larval trophic modes, with genes involved in lipid metabolism and chaetogenesis over expressed in planktotrophic larvae. In contrast, up-regulated genes in adelphophagic larvae were associated with DNA replication and mRNA synthesis.


2005 ◽  
Vol 3 (2) ◽  
pp. 410-412 ◽  
Author(s):  
C. J. F. DE WOLF ◽  
R. M. J. CUPERS ◽  
R. M. BERTINA ◽  
H. L. VOS

1992 ◽  
Vol 38 (6) ◽  
pp. 555-562 ◽  
Author(s):  
Vipin Rastogi ◽  
Monika Labes ◽  
Turlough Finan ◽  
Robert Watson

Symbiotic nitrogen fixation may be limited by the transport of C4 dicarboxylates into bacteroids in the nodule for use as a carbon and energy source. In an attempt to increase dicarboxylate transport, a plasmid was constructed in which the Rhizobium meliloti structural transport gene dctA was fused to a tryptophan operon promoter from Salmonella typhimurium, trpPO. This resulted in a functional dctA gene that was no longer under the control of the dctBD regulatory genes, but the recombinant plasmid was found to be unstable in R. meliloti. To stably integrate the trpPO-dctA fusion, it was recloned into pBR325 and recombined into the R. meliloti exo megaplasmid in the dctABD region. The resultant strain showed constitutive dctA-specific mRNA synthesis which was about 5-fold higher than that found in fully induced wild-type cells. Uptake assays showed that [14C]succinate transport by the trpPO-dctA fusion strain was constitutive, and the transport rate was the same as that of induced control cells. Acetylene reduction assays indicated a significantly higher rate of nitrogen fixation in plants inoculated with the trpPO-dctA fusion strain compared with the control. Despite this apparent increase, the plants had the same top dry weights as those inoculated with control cells. Key words: acetylene reduction, genetic engineering, nodule, plasmid stability, promoter.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Francesca Cammarota ◽  
Gabriella de Vita ◽  
Marco Salvatore ◽  
Mikko O. Laukkanen

Extracellular superoxide dismutase (SOD3) is a secreted enzyme that uses superoxide anion as a substrate in a dismutase reaction that results in the formation of hydrogen peroxide. Both of these reactive oxygen species affect growth signaling in cells. Although SOD3 has growth-supporting characteristics, the expression ofSOD3is downregulated in epithelial cancer cells. In the current work, we studied the mechanisms regulatingSOD3expressionin vitrousing thyroid cell models representing different stages of thyroid cancer. We demonstrate that a low level of RAS activation increasesSOD3mRNA synthesis that then gradually decreases with increasing levels of RAS activation and the decreasing degree of differentiation of the cancer cells. Our data indicate thatSOD3regulation can be divided into two classes. The first class involves RAS–driven reversible regulation ofSOD3expression that can be mediated by the following mechanisms: RAS GTPase regulatory genes that are responsible forSOD3self-regulation; RAS-stimulated p38 MAPK activation; and RAS-activated increased expression of themir21microRNA, which inversely correlates withsod3mRNA expression. The second class involves permanent silencing ofSOD3mediated by epigenetic DNA methylation in cells that represent more advanced cancers. Therefore, the work suggests thatSOD3belongs to the group ofrasoncogene-silenced genes.


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