scholarly journals Arabidopsis Nuclear-Encoded Plastid Transit Peptides Contain Multiple Sequence Subgroups with Distinctive Chloroplast-Targeting Sequence Motifs

2008 ◽  
Vol 20 (6) ◽  
pp. 1603-1622 ◽  
Author(s):  
Dong Wook Lee ◽  
Jong Kyoung Kim ◽  
Sumin Lee ◽  
Seungjin Choi ◽  
Sanguk Kim ◽  
...  
2018 ◽  
Vol 38 (2) ◽  
Author(s):  
Shohei Yokoo ◽  
Seiya Inoue ◽  
Nana Suzuki ◽  
Naho Amakawa ◽  
Hidenori Matsui ◽  
...  

Isochorismate synthase (ICS) converts chorismate into isochorismate, a precursor of primary and secondary metabolites including salicylic acid (SA). SA plays important roles in responses to stress conditions in plants. Many studies have suggested that the function of plant ICSs is regulated at the transcriptional level. In Arabidopsis thaliana, the expression of AtICS1 is induced by stress conditions in parallel with SA synthesis, and AtICS1 is required for SA synthesis. In contrast, the expression of NtICS is not induced when SA synthesis is activated in tobacco, and it is unlikely to be involved in SA synthesis. Studies on the biochemical properties of plant ICSs are limited, compared with those on transcriptional regulation. We analyzed the biochemical properties of four plant ICSs: AtICS1, NtICS, NbICS from Nicotiana benthamiana, and OsICS from rice. Multiple sequence alignment analysis revealed that their primary structures were well conserved, and predicted key residues for ICS activity were almost completely conserved. However, AtICS1 showed much higher activity than the other ICSs when expressed in Escherichia coli and N. benthamiana leaves. Moreover, the levels of AtICS1 protein expression in N. benthamiana leaves were higher than the other ICSs. Construction and analysis of chimeras between AtICS1 and OsICS revealed that the putative chloroplast transit peptides (TPs) significantly affected the levels of protein accumulation in N. benthamiana leaves. Chimeric and point-mutation analyses revealed that Thr531, Ser537, and Ile550 of AtICS1 are essential for its high activity. These distinct biochemical properties of plant ICSs may suggest different roles in their respective plant species.


1987 ◽  
Vol 7 (12) ◽  
pp. 4185-4193
Author(s):  
K A Roebuck ◽  
R J Walker ◽  
W E Stumph

The DNA sequence requirements of chicken U1 RNA gene expression have been examined in an oocyte transcription system. An enhancer region, which was required for efficient U1 RNA gene expression, is contained within a region of conserved DNA sequences spanning nucleotide positions -230 to -183, upstream of the transcriptional initiation site. These DNA sequences can be divided into at least two distinct subregions or domains that acted synergistically to provide a greater than 20-fold stimulation of U1 RNA synthesis. The first domain contains the octamer sequence ATGCAAAT and was recognized by a DNA-binding factor present in HeLa cell extracts. The second domain (the SPH domain) consists of conserved sequences immediately downstream of the octamer and is an essential component of the enhancer. In the oocyte, the DNA sequences of the SPH domain were able to enhance gene expression at least 10-fold in the absence of the octamer domain. In contrast, the octamer domain, although required for full U1 RNA gene activity, was unable to stimulate expression in the absence of the adjacent downstream DNA sequences. These findings imply that sequences 3' of the octamer play a major role in the function of the chicken U1 RNA gene enhancer. This concept was supported by transcriptional competition studies in which a cloned chicken U4B RNA gene was used to compete for limiting transcription factors in oocytes. Multiple sequence motifs that can function in a variety of cis-linked configurations may be a general feature of vertebrate small nuclear RNA gene enhancers.


The discovery of enzymes with lipolytic activities in all kingdoms of life from prokaryote to eukaryote species raises the possibility of the presence of an evolutionary relationship history of these proteins among many species of various living organisms. The chapter suggests a strategy based on the phylogenetic distribution and homology conservation in plant lipolytic enzymes for possible depiction of their biological evolution. Extensive databases and online resources for lipidomics and related areas are useful tools to analyze the different lipolytic enzymes in the three major super kingdoms of life, including higher plants kingdom and confined organisms such as algae that have recently gained much interest due to their promising potential applications in lipids hydrolysis and biosynthesis. Multiple sequence alignments of the identified lipolytic enzymes from databases could serve to the identification of globally conserved residues as well as conserved sequence motifs. Estimation of evolutionary distance between the various identified lipolytic enzymes could also be carried out to better understand the pattern of evolution.


2015 ◽  
Vol 169 (1) ◽  
pp. 471-484 ◽  
Author(s):  
Dong Wook Lee ◽  
Seungjin Woo ◽  
Kyoung Rok Geem ◽  
Inhwan Hwang

2020 ◽  
Author(s):  
Lalitha Guruprasad

<div>Coronavirus disease 2019 (COVID-19) is a pandemic infectious disease caused by novel Severe Acute Respiratory Syndrome coronavirus-2 (SARS CoV-2). The SARS CoV-2 is transmitted more rapidly and readily than SARS CoV. Both, SARS CoV and SARS CoV-2 via their glycosylated spike proteins recognize the human angiotensin converting enzyme-2 (ACE-2) receptor. We generated multiple sequence alignments and phylogenetic trees for representative spike proteins of CoV and CoV-2 from various host sources in order to analyze the specificity in SARS CoV-2 spike proteins required for causing infection in humans. Our results show that two sequence motifs in the N-terminal domain; "MESEFR" and "SYLTPG" are specific to human SARS CoV-2 and pangolin SARS CoV. In the receptor binding domain (RBD), three sequence loops; VGGNY (loop 1), YQAGSTPC (loop 2), EGFNCY (loop 3) and a tethered disulfide bridge Cys480-Cys488 connecting loops 2 and 3 are structural determinants for the recognition of human ACE-2 receptor. The complete genome analysis of representative SARS CoVs from bat, civet, pangolin, human host sources and human SARS CoV-2 identified the bat genome (GenBank code: MN996532.1) and the pangolin SARS CoV genomes as closest to the recent novel human SARS CoV-2 genomes. The bat CoV genomes (GenBank codes: MG772933 and MG772934) are evolutionary intermediates in the mutagenesis progression towards becoming human SARS CoV-2. </div>


2003 ◽  
Vol 23 (17) ◽  
pp. 5959-5971 ◽  
Author(s):  
Hui Zhu ◽  
Robert A. Hasman ◽  
Katherine M. Young ◽  
Nancy L. Kedersha ◽  
Hua Lou

ABSTRACT Alternative RNA processing of human calcitonin/CGRP pre-mRNA is regulated by an intronic enhancer element. Previous studies have demonstrated that multiple sequence motifs within the enhancer and a number of trans-acting factors play critical roles in the regulation. Here, we report the identification of TIAR as a novel player in the regulation of human calcitonin/CGRP alternative RNA processing. TIAR binds to the U tract sequence motif downstream of a pseudo 5′ splice site within the previously characterized intron enhancer element. Binding of TIAR promotes inclusion of the alternative 3′-terminal exon located more than 200 nucleotides upstream from the U tract. In cells that preferentially include this exon, overexpression of a mutant TIAR that lacks the RNA binding domains suppressed inclusion of this exon. In this report, we also demonstrate an unusual novel interaction between U6 snRNA and the pseudo 5′ splice site, which was shown previously to bind U1 snRNA. Interestingly, TIAR binding to the U tract sequence depends on the interaction of not only U1 but also U6 snRNA with the pseudo 5′ splice site. Conversely, TIAR binding promotes U6 snRNA binding to its target. The synergistic relationship between TIAR and U6 snRNA strongly suggests a novel role of U6 snRNP in regulated alternative RNA processing.


1986 ◽  
Vol 5 (2) ◽  
pp. 387-397 ◽  
Author(s):  
M. Zenke ◽  
T. Grundström ◽  
H. Matthes ◽  
M. Wintzerith ◽  
C. Schatz ◽  
...  

2016 ◽  
Vol 5 (2) ◽  
pp. 28
Author(s):  
Mohamed Tahar Ben Othman

Multiple Sequence Alignment (MSA) is used in genomic analysis, such as the identification of conserved sequence motifs, the estimation of evolutionary divergence between sequences, and the genes’ historical relationships inference. Several researches were conducted to determine the level of similarity of a set of sequences. Due to the problem of the NP-complete class property, a number of researches use genetic algorithms (GA) to find a solution to the multiple sequence alignment. However, the nature of genetic algorithms makes the complexity extremely high due to the redundancy provided by the different operators. The aim of this paper is to study some proposed GA solutions provided for MSA and to compare them using some criteria which we believe any solution should comply with in matters of representativeness, closeness and original sequence invariance.


Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1165-1176 ◽  
Author(s):  
María del Carmen Vargas ◽  
Sergio Encarnación ◽  
Araceli Dávalos ◽  
Agustín Reyes-Pérez ◽  
Yolanda Mora ◽  
...  

The plasmid-borne Rhizobium etli katG gene encodes a dual-function catalase-peroxidase (KatG) (EC 1.11.1.7) that is inducible and heat-labile. In contrast to other rhizobia, katG was shown to be solely responsible for catalase and peroxidase activity in R. etli. An R. etli mutant that did not express catalase activity exhibited increased sensitivity to hydrogen peroxide (H2O2). Pre-exposure to a sublethal concentration of H2O2 allowed R. etli to adapt and survive subsequent exposure to higher concentrations of H2O2. Based on a multiple sequence alignment with other catalase-peroxidases, it was found that the catalytic domains of the R. etli KatG protein had three large insertions, two of which were typical of KatG proteins. Like the katG gene of Escherichia coli, the R. etli katG gene was induced by H2O2 and was important in sustaining the exponential growth rate. In R. etli, KatG catalase-peroxidase activity is induced eightfold in minimal medium during stationary phase. It was shown that KatG catalase-peroxidase is not essential for nodulation and nitrogen fixation in symbiosis with Phaseolus vulgaris, although bacteroid proteome analysis indicated an alternative compensatory mechanism for the oxidative protection of R. etli in symbiosis. Next to, and divergently transcribed from the catalase promoter, an ORF encoding the regulator OxyR was found; this is the first plasmid-encoded oxyR gene described so far. Additionally, the katG promoter region contained sequence motifs characteristic of OxyR binding sites, suggesting a possible regulatory mechanism for katG expression.


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