Multiple Mechanisms for Degradation of Bacteriophage T4 soc mRNA

Genetics ◽  
2002 ◽  
Vol 160 (1) ◽  
pp. 5-12
Author(s):  
Toshie Kai ◽  
Tetsuro Yonesaki

Abstract The dmd gene of bacteriophage T4 is required for regulation of mRNA stability in a stage-dependent manner during infection. When this gene is mutated, late genes are globally silenced because of rapid degradation of mRNAs. To investigate the mechanism of such mRNA degradation, we analyzed the late gene soc transcripts. The degradation of soc mRNA was remarkably stabilized when its ability to be translated was impaired; either disruption of translation initiation signals or elimination of termination codons was effective in stabilization of soc mRNA and removal of elongation modestly stabilized it. Even in the absence of translation, however, the residual activity was still significant. These results suggested that the degradation of soc transcripts was promoted by two different mechanisms; one is dependent on translation and the other independent of translation. We found several cleavages introduced into soc RNA specifically when the dmd gene was mutated; some of them could be linked to polypeptide chain elongation and termination, suggesting the correlation with ribosomal action, and the others were independent of translation.

Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 7-17 ◽  
Author(s):  
Hiroyuki Ueno ◽  
Tetsuro Yonesaki

Abstract Gene 61.5 of bacteriophage T4 has a unique role in gene expression. When this gene is mutated, mRNAs of many late genes are rapidly degraded, resulting in late-gene silencing. Here, we characterize an extragenic suppressor, ssf5, of a gene 61.5 mutation. ssf5 was found to be an amber mutation in motA, which encodes a transcription activator for T4 middle genes. When this gene is mutated, both degradation and specific cleavage of late-gene mRNA is induced after a delay, as exemplified by soc mRNA. Consequently, partial late-gene expression occurs. In an ssf5 genetic background, a gene 61.5 mutation exhibits a novel phenotype: in contrast to late-gene mRNA, middle-gene mRNA is stabilized and the expression of middle genes is prolonged. This is attributable to an activity of gene 61.5 specific for degradation of middle-gene mRNA. The degradation of middle-gene mRNA in the presence of a normal gene 61.5 appears in parallel with the degradation of late-gene mRNA in its absence. This observation suggests that the mRNA-degrading activity that silences late genes in cells infected with a gene 61.5 mutant is targeted to middle-gene mRNA when gene 61.5 is wild type. These results and the results obtained in the presence of a normal motA gene suggest that gene 61.5 protein functions to discriminate mRNAs for degradation in a stage-dependent manner.


2018 ◽  
Vol 29 (8) ◽  
pp. 975-987 ◽  
Author(s):  
Baojin Ding ◽  
Paul R. Dobner ◽  
Debra Mullikin-Kilpatrick ◽  
Wei Wang ◽  
Hong Zhu ◽  
...  

How intrinsic and extrinsic signals are coordinated to regulate synaptic maturation and its timing is an important question for neurodevelopment and its disorders. We investigated the influence of the neurotrophin BDNF on the developmental timing of a dendrite/synapse-related gene program controlled by nuclear factor I (NFI) in maturing cerebellar granule neurons (CGNs). BDNF accelerated the onset of NFI-regulated late-gene expression and NFI temporal occupancy in CGN cultures in a MEK5/ERK5-dependent manner. BDNF and NFI occupancy were mutually regulating, with BDNF enhancing the temporal binding of NFI to the Bdnf4 promoter itself. Moreover, BDNF induced phosphorylation and accelerated the departure of the trans-repressor NFATc4 from NFI late-gene promoters, including Bdnf4, which is permissive for NFI binding. BDNF dismissal of NFATc4 from late genes was linked to MEK5/ERK5-dependent sequestration of NFATc4 in the cis–Golgi, an event mirrored in CGNs developing in vivo. These studies reveal an expanded autoregulatory gene network for NFI temporal occupancy involving BDNF and NFATc4 extranuclear sequestration. Based on these and earlier findings, NFATc4 integrates intrinsic developmental signaling from membrane potential/calcineurin and autocrine/paracrine BDNF/TrkB to control initiation of NFI occupancy in maturing CGNs. We also identify a local Bdnf/Etv1 gene circuit within the larger NFI autoregulatory network.


Genetics ◽  
1996 ◽  
Vol 144 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Toshie Kai ◽  
Harold E Selick ◽  
Tetsuro Yonesaki

Abstract We identified a novel gene of bacteriophage T4, gene 61.5, which appears to be involved in protein synthesis late in infection. Northern blot analysis revealed that a mutant of 61.5 accumulated truncated transcripts of representative late genes. Using a double mutant of genes 61.5 and 55, which prevents transcription of late genes, we demonstrate that even transcripts of middle genes, while full-length when initially expressed, are similarly truncated at later stages of infection. These results indicate that the abnormality in transcript length occurs late in infection, regardless of whether the transcript derives from a middle or a late gene. Primer-extension analysis revealed that the 5′ ends of the late gene 23 transcripts that accumulated in gene 61.5 mutant-infected cells were located at internal discrete sites as well as at the expected transcription start site. Moreover, the decay rates of full-length transcripts from genes uvsY or 45 were more than twofold faster in the absence of a functional gene 61.5. These results suggest that mutation of gene 61.5 activates endonucleolytic cleavage of middle and late transcripts, probably by RNase M.


1981 ◽  
Vol 39 (1) ◽  
pp. 31-45 ◽  
Author(s):  
K A Jacobs ◽  
L M Albright ◽  
D K Shibata ◽  
E P Geiduschek

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 734
Author(s):  
Xuhua Xia

The design of Pfizer/BioNTech and Moderna mRNA vaccines involves many different types of optimizations. Proper optimization of vaccine mRNA can reduce dosage required for each injection leading to more efficient immunization programs. The mRNA components of the vaccine need to have a 5’-UTR to load ribosomes efficiently onto the mRNA for translation initiation, optimized codon usage for efficient translation elongation, and optimal stop codon for efficient translation termination. Both 5’-UTR and the downstream 3’-UTR should be optimized for mRNA stability. The replacement of uridine by N1-methylpseudourinine () complicates some of these optimization processes because is more versatile in wobbling than U. Different optimizations can conflict with each other, and compromises would need to be made. I highlight the similarities and differences between Pfizer/BioNTech and Moderna mRNA vaccines and discuss the advantage and disadvantage of each to facilitate future vaccine improvement. In particular, I point out a few optimizations in the design of the two mRNA vaccines that have not been performed properly.


Genetics ◽  
1972 ◽  
Vol 70 (1) ◽  
pp. 175-180
Author(s):  
LaDonna Immken ◽  
David Apirion

ABSTRACT 3″,5″ cyclic-AMP (cAMP) will stimulate the rate of tryptophanase synthesis in Escherichia coli cultures induced with tryptophan. Adding cAMP after the initiation of messenger RNA synthesis was blocked by rifampicin, did not stimulate tryptophanase synthesis. This indicates that cAMP acts at initiation of either transcription or translation and not at the level of chain elongation of either the messenger or the polypeptide chain.


2018 ◽  
Vol 93 (1) ◽  
Author(s):  
Angelica F. Castañeda ◽  
Britt A. Glaunsinger

ABSTRACTIn the beta- and gammaherpesviruses, a specialized complex of viral transcriptional activators (vTAs) coordinate to direct expression of virus-encoded late genes, which are critical for viral assembly and whose transcription initiates only after the onset of viral DNA replication. The vTAs in Kaposi’s sarcoma-associated herpesvirus (KSHV) are ORF18, ORF24, ORF30, ORF31, ORF34, and ORF66. While the general organization of the vTA complex has been mapped, the individual roles of these proteins and how they coordinate to activate late gene promoters remain largely unknown. Here, we performed a comprehensive mutational analysis of the conserved residues in ORF18, which is a highly interconnected vTA component. Surprisingly, the mutants were largely selective for disrupting the interaction with ORF30 but not the other three ORF18 binding partners. Furthermore, disrupting the ORF18-ORF30 interaction weakened the vTA complex as a whole, and an ORF18 point mutant that failed to bind ORF30 was unable to complement an ORF18 null virus. Thus, contacts between individual vTAs are critical as even small disruptions in this complex result in profound defects in KSHV late gene expression.IMPORTANCEKaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi’s sarcoma and other B-cell cancers and remains a leading cause of death in immunocompromised individuals. A key step in the production of infectious virions is the transcription of viral late genes, which generates capsid and structural proteins and requires the coordination of six viral proteins that form a complex. The role of these proteins during transcription complex formation and the importance of protein-protein interactions are not well understood. Here, we focused on a central component of the complex, ORF18, and revealed that disruption of its interaction with even a single component of the complex (ORF30) prevents late gene expression and completion of the viral lifecycle. These findings underscore how individual interactions between the late gene transcription components are critical for both the stability and function of the complex.


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