scholarly journals Functional characterization and structural modelling of late gene expression factor 4 from Bombyx mori nucleopolyhedrovirus

2002 ◽  
Vol 368 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Seema SEHRAWAT ◽  
Narayanaswamy SRINIVASAN ◽  
Karumathil P. GOPINATHAN
Keyword(s):  
Gene Expression ◽  
Bombyx Mori ◽  
Functional Characterization ◽  
Three Dimensional ◽  
Late Gene ◽  
Transferase Activity ◽  
Late Gene Expression ◽  
Bombyx Mori Nucleopolyhedrovirus ◽  
Mrna Capping ◽  
Capping Enzymes

Late gene expression factor 4 (LEF4), a multifunctional protein encoded by the Bombyx mori nucleopolyhedrovirus has been bacterially expressed and characterized. Sequence analyses and three-dimensional modelling of B. mori LEF4 showed that the protein is related to mRNA-capping enzymes, which are organized as two modular domains. Most of the acidic side chains in LEF4 were solvent-exposed and spread all along the fold. A region dominated by negatively charged groups, which protrudes from the larger domain was ideally suited for interactions with proteins having positively charged patches at the surface. The purified LEF4 protein exhibited different enzyme activities associated with mRNA-capping enzymes, i.e. GTP-binding, RNA triphosphatase and guanylate transferase activities. In addition, LEF4 also showed NTP-hydrolysing activity. The kinetic analysis of ATP hydrolysis revealed a sigmoidal response with two deduced binding sites for ATP, whereas the guanylate transferase activity showed a typical hyperbolic response to varying concentrations of GTP with a Km of 330±20μM. Analysis of the modelled three-dimensional structure of LEF4 suggested the presence of crucial residues in sequence motifs important for the integrity of the fold. Mutation of one such conserved and buried tyrosine residue to cysteine in the motif IIIa, located close to the interlobe region of the model, resulted in a 44% loss of guanylate transferase activity of LEF4 but had no effect on the ATPase activity.

Characterization of late gene expression factor LEF-10 from Bombyx mori nucleopolyhedrovirus

2013 ◽  
Vol 175 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Wei Yu ◽  
Chao-Yi Du ◽  
Yan-Ping Quan ◽  
Zuo-Ming Nie ◽  
Jian Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bombyx Mori ◽  
Late Gene ◽  
Late Gene Expression ◽  
Bombyx Mori Nucleopolyhedrovirus

scholarly journals Characterization of late gene expression factors lef-9 and lef-8 from Bombyx mori nucleopolyhedrovirus

2002 ◽  
Vol 83 (8) ◽  
pp. 2015-2023 ◽  
Author(s):  
Asha Acharya ◽  
Karumathil P. Gopinathan
Keyword(s):  
Gene Expression ◽  
Bombyx Mori ◽  
Late Gene ◽  
Late Gene Expression ◽  
Reading Frame ◽  
Early Transcription ◽  
A Site ◽  
Translational Termination

Late gene expression factors, LEF-4, LEF-8, LEF-9 and P47 constitute the primary components of the Autographa californica multinucleocapsid polyhedrovirus (AcMNPV)-encoded RNA polymerase, which initiates transcription from late and very late promoters. Here, characterization of lef-9 and lef-8, which encode their corresponding counterparts, from Bombyx mori NPV is reported. Transcription of lef-9 initiated at two independent sites: from a GCACT sequence located at −38 nt and a CTCTT sequence located at −50 nt, with respect to the +1 ATG of the open reading frame. The 3′ end of the transcript was mapped to a site 17 nt downstream of a canonical polyadenylation signal located 7 nt downstream of the first of the two tandem translational termination codons. Maximum synthesis of LEF-9 was seen from 36 h post-infection (p.i.). The transcription of lef-8 initiated early in infection from a GTGCAAT sequence that differed in the corresponding region from its AcMNPV counterpart (GCGCAGT), with consequent elimination of the consensus early transcription start site motif (underlined). Peak levels of lef-8 transcripts were attained by 24 h p.i. Immunocopurification analyses suggested that there was an association between LEF-8 and LEF-9 in vivo.

scholarly journals Prolonged activation of NF-κB by human cytomegalovirus promotes efficient viral replication and late gene expression

Virology ◽  
2006 ◽  
Vol 346 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Ian B. DeMeritt ◽  
Jagat P. Podduturi ◽  
A. Michael Tilley ◽  
Maciej T. Nogalski ◽  
Andrew D. Yurochko
Keyword(s):  
Gene Expression ◽  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Late Gene ◽  
Late Gene Expression ◽  
Efficient Viral Replication

scholarly journals An immediate–late gene expression module decodes ERK signal duration

2017 ◽  
Vol 13 (5) ◽  
pp. 928 ◽  
Author(s):  
Florian Uhlitz ◽  
Anja Sieber ◽  
Emanuel Wyler ◽  
Raphaela Fritsche‐Guenther ◽  
Johannes Meisig ◽  
...  
Keyword(s):  
Gene Expression ◽  
Signal Duration ◽  
Late Gene ◽  
Late Gene Expression ◽  
Expression Module

scholarly journals Systematic functional characterization of antisense eRNA of protocadherin α composite enhancer

2021 ◽  
Vol 35 (19-20) ◽  
pp. 1383-1394
Author(s):  
Yuxiao Zhou ◽  
Siyuan Xu ◽  
Mo Zhang ◽  
Qiang Wu
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Single Cells ◽  
Functional Characterization ◽  
Three Dimensional ◽  
Elongation Factor ◽  
Locked Nucleic Acid ◽  
Loop Formation ◽  
Long Distance ◽  
Enhancer Region

Enhancers generate bidirectional noncoding enhancer RNAs (eRNAs) that may regulate gene expression. At present, the eRNA function remains enigmatic. Here, we report a 5′ capped antisense eRNA PEARL (Pcdh eRNA associated with R-loop formation) that is transcribed from the protocadherin (Pcdh) α HS5-1 enhancer region. Through loss- and gain-of-function experiments with CRISPR/Cas9 DNA fragment editing, CRISPRi, and CRISPRa, as well as locked nucleic acid strategies, in conjunction with ChIRP, MeDIP, DRIP, QHR-4C, and HiChIP experiments, we found that PEARL regulates Pcdhα gene expression by forming local RNA–DNA duplexes (R-loops) in situ within the HS5-1 enhancer region to promote long-distance chromatin interactions between distal enhancers and target promoters. In particular, increased levels of eRNA PEARL via perturbing transcription elongation factor SPT6 lead to strengthened local three-dimensional chromatin organization within the Pcdh superTAD. These findings have important implications regarding molecular mechanisms by which the HS5-1 enhancer regulates stochastic Pcdhα promoter choice in single cells in the brain.

scholarly journals Gene D5 product of bacteriophage T5: DNA-binding protein affecting DNA replication and late gene expression.

1979 ◽  
Vol 29 (1) ◽  
pp. 322-327 ◽  
Author(s):  
D J McCorquodale ◽  
J Gossling ◽  
R Benzinger ◽  
R Chesney ◽  
L Lawhorne ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Replication ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Late Gene ◽  
Late Gene Expression ◽  
Bacteriophage T5
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