scholarly journals Identification and evolution of Cas9 tracrRNAs

2020 ◽  
Author(s):  
Shane K. Dooley ◽  
Erica K. Baken ◽  
Walter Moss ◽  
Adina Howe ◽  
Joshua K. Young

AbstractCas9 trans-activating CRISPR RNAs (tracrRNAs) form distinct structures essential for target recognition and cleavage and dictate exchangeability between orthologous proteins. As non-coding RNAs that are often apart from the CRISPR array, their identification can be arduous. In this paper, a new bioinformatic method for the detection of Cas9 tracrRNAs is presented. The approach utilizes a co-variance model (CM) based on both sequence homology and predicted secondary structure to locate tracrRNAs. This method predicts a tracrRNA for 98% of CRISPR-Cas9 systems identified by us. The identified tracrRNAs exhibit wide variation in sequence identity, however, CM analyses allow 94.7% to be categorized into just 10 related groups. Finally, association between Cas9 amino acid sequence-based phylogeny and tracrRNA secondary structure is evaluated, revealing strong evidence that secondary structure is evolutionarily conserved among Cas9 lineages. Altogether, our findings provide insight into Cas9 tracrRNA evolution and efforts to characterize the tracrRNA of new Cas9 systems.

1990 ◽  
Vol 55 (3) ◽  
pp. 950-955 ◽  
Author(s):  
Trudy J. Milne ◽  
Annette R. Atkins ◽  
Juanita A. Warren ◽  
Wendy P. Auton ◽  
Ross Smith

2001 ◽  
Vol 82 (12) ◽  
pp. 2869-2879 ◽  
Author(s):  
Frederick S. B. Kibenge ◽  
Molly J. T. Kibenge ◽  
Patricia K. McKenna ◽  
Paul Stothard ◽  
Rebecca Marshall ◽  
...  

Infectious salmon anaemia virus (ISAV), an orthomyxovirus-like virus, is an important fish pathogen in marine aquaculture. Virus neutralization of 24 ISAV isolates in the TO cell line using rabbit antisera to the whole virus and comparative sequence analysis of their haemagglutinin (HA) genes have allowed elaboration on the variation of ISAV isolates. The 24 viruses were neutralized to varying degrees, revealing two major antigenic groups, one American and one European. Sequence analysis of the HA gene also revealed two groups of viruses (genotypes) that correlated with the antigenic groupings. The two HA subtypes had nucleotide sequence identity of only ⩽79·4% and amino acid sequence identity of ⩽84·5% whereas, within each subtype, the sequence identities were 90·7% or higher. This grouping was also evident upon phylogenetic analysis, which revealed two distinct phylogenetic families. Between the two groups, the amino acid sequence was most variable in the C-terminal region and included deletions of 4–16 amino acids in all isolates relative to ISAV isolate RPC/NB-980 280-2. In order to view the relationships among these sequences and the HA sequences of the established orthomyxoviruses, a second phylogenetic tree was constructed which showed the ISAV sequences to be more closely related to sequences from Influenzavirus A and Influenzavirus B than to sequences from Influenzavirus C and Thogotovirus. The extensive deletions in the gene of European ISAV isolates lead us to speculate that the archetypal ISAV was probably of Canadian origin.


1983 ◽  
Vol 3 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Hans Jórnvall ◽  
Bengt Persson

Distributions of amino acid residues in proteins show that proline is overrepresented in sequence positions following two basic residues ({LysArg}−{LysArg}), i.e. at sites similar to those susceptible to proteolytic cleavages of hormonal pro-forms. Conformational correlations further show that {LysArg}−{LysArg}-Pro sequences are often (8/11) not adiacent to elements of secondary structure, whereas the opposite applies to {LysArg}−{LysArg}-nonPro sequences (82/103 adjacent to elements of secondary structure). These distribution patterns from proteins in general also seem applicable in individual protein groups as demonstrated for some dehydrogenases. It appears possible that {LysArg}−{LysArg}-nonPro constitutes a restricted sequence, n proteins, and that proline, in addition to elements of secondary structure, contributes a means of avoiding unacceptable proteolytic processings of proteins in general.


2018 ◽  
Vol 62 (10) ◽  
Author(s):  
L. Dabos ◽  
A. B. Jousset ◽  
R. A. Bonnin ◽  
N. Fortineau ◽  
A. Zavala ◽  
...  

ABSTRACT OXA-535 is a chromosome-encoded carbapenemase of Shewanella bicestrii JAB-1 that shares only 91.3% amino acid sequence identity with OXA-48. Catalytic efficiencies are similar to those of OXA-48 for most β-lactams, except for ertapenem, where a 2,000-fold-higher efficiency was observed with OXA-535. OXA-535 and OXA-436, a plasmid-encoded variant of OXA-535 differing by three amino acids, form a novel cluster of distantly related OXA-48-like carbapenemases. Comparison of blaOXA-535 and blaOXA-436 genetic environments suggests that an ISCR1 may be responsible for blaOXA-436 gene mobilization from the chromosome of Shewanella spp. to plasmids.


Zygote ◽  
2002 ◽  
Vol 10 (4) ◽  
pp. 291-299 ◽  
Author(s):  
Christine A. Swann ◽  
Rory M. Hope ◽  
William G. Breed

This comparative study of the cDNA sequence of the zona pellucida C (ZPC) glycoprotein in murid rodents focuses on the nucleotide and amino acid sequence of the putative sperm-combining site. We ask the question: Has divergence evolved in the nucleotide sequence of ZPC in the murid rodents of Australia? Using RT-PCR and (RACE) PCR, the complete cDNA coding region of ZPC in the Australian hydromyine rodents Notomys alexis and Pseudomys australis, and a partial cDNA sequence from a third hydromyine rodent, Hydromys chrysogaster, has been determined. Comparison between the cDNA sequences of the hydromyine rodents reveals that the level of amino acid sequence identity between N. alexis and P. australis is 96%, whereas that between the two species of hydromyine rodents and M. musculus and R. norvegicus is 88% and 87% respectively. Despite being reproductively isolated from each other, the three species of hydromyine rodents have a 100% level of amino acid sequence identity at the putative sperm-combining site. This finding does not support the view that this site is under positive selective pressure. The sequence data obtained in this study may have important conservation implications for the dissemination of immunocontraception directed against M. musculus using ZPC antibodies.


2005 ◽  
Vol 52 (4) ◽  
pp. 857-862 ◽  
Author(s):  
Lina Liu ◽  
Shicui Zhang ◽  
Zhenhui Liu ◽  
Hongyan Li ◽  
Mei Liu ◽  
...  

The complete cDNA and deduced amino-acid sequences of ribosomal proteins L34 (AmphiL34) and S29 (AmphiS29) from the amphioxus Branchiostoma belcheri tsingtauense were identified in this study. The AmphiL34 cDNA is 435 nucleotides in length and encodes a 118 amino-acid protein with calculated molecular mass of 13.6 kDa. It shares 53.6-67.5% amino-acid sequence identity with its eukaryotic counterparts including human, mouse, rat, pig, frog, catfish, fruit fly, mosquito, armyworm, nematode and yeast. The AmphiS29 cDNA comprises 453 nucleotides and codes for a 56 amino-acid protein with a calculated molecular mass of 6.6 kDa. It shows 66.1-78.6% amino-acid sequence identity to eukaryotic S29 proteins from human, mouse, rat, pig, zebrafish, seahorse, fruit fly, nematode, sea hare and yeast. AmphiL34 contains a putative nucleolar localization signal, while AmphiS29 has a zinc finger-like domain. A phylogenetic tree deduced from the conserved sequences of AmphiL34 and AmphiS29 and other known counterparts indicates that the positions of AmphiL34/AmphiS29 are intermediate between the vertebrate and invertebrate L34/S29. Southern blot analysis demonstrates the presence of one copy of the L34 gene and 2-3 copies of the S29 gene in the genome of the amphioxus B. belcheri tsingtauense. This is in sharp contrast to the existence of 7-9 copies of the L34 gene and 14-17 copies of the S29 gene in the rat genome. These date suggest that housekeeping genes like AmphiL34 and AmphiS29 have undergone large-scale duplication in the chordate lineage.


Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 112-112 ◽  
Author(s):  
N. Borodynko ◽  
B. Hasiów ◽  
H. Pospieszny

Beet necrotic yellow vein virus (BNYVV), the casual agent of rhizomania disease, was identified in sugar beet plants from several fields in the Wielkopolska Region of Poland (1). In greenhouse studies, sugar beets were grown in the soil from one of these fields to bait soilborne viruses. Of 200 sugar beet plants, three developed symptoms of vein clearing, vein banding, and mosaic. Crude sap from symptomatic plants was used for mechanical inoculation of various plants species. In Chenopodium quinoa, C. amaranticolor, and Tetragonia expansa only local lesions were observed. Electron microscope examination of negatively stained leaf-dip preparations from symptomatic sugar beet plants showed a mixture of rod-shape particles from 70 to 400 nm long. Using double-antibody sandwich enzyme-linked immunosorbent assay tests, two symptomatic sugar beet plants gave positive reactions with antiserum against BNYVV (Bio-Rad, Hercules, CA) and a third plant gave a positive reaction with antisera against BNYVV and Beet soilborne virus (BSBV). Total RNA was extracted from roots and leaves of the symptomatic plants and used in a multiplex reverse transcription-polymerase chain reaction (mRT-PCR) assay. Specific primers were designed to amplify a fragment of the RNA1 for BSBV and RNA2 for BNYVV and Beet virus Q (BVQ) (2). Two mRT-PCR products amplified with the primers specific to BNYVV and BSBV were obtained and sequenced. A 274-nt amplicon sequence (GenBank Accession No. DQ012156) had 98% nucleotide sequence identity with the German BNYVV isolate F75 (GenBank Accession No. AF19754) and a 376-nt amplicon sequence (GenBank Accession No. AY999690) had 98% nucleotide and 98% amino acid sequence identity with the German BSBV isolate (GenBank Accession No. Z97873). The Polish BSBV isolate had 88% nucleotide and 62% amino acid sequence identity with BVQ, another pomovirus (GenBank Accession No. AJ 223596 formerly known as serotype Wierthe of BSBV (2). In 2005, mRT-PCR was used on samples collected from two fields of the Wielkopolska Region. Of 15 tested sugar beet plants, 12 gave positive reactions with primers specific for BSBV and nine with primers specific to BNYVV. To our knowledge, this is first report of BSBV in Poland. In Europe, BSBV was previously reported in England, the Netherlands, Belgium, Sweden, Germany, France, and Finland (2,3). References: (1) M. Jezewska and J. Piszczek. Phytopathol. Polonica, 21:165, 2001. (2) A. Maunier et al. Appl. Environ. Microbiol. 69:2356, 2003. (3) C. M. Rush and G. B. Heidel. Plant Dis. 79:868, 1995.


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