scholarly journals Complete sequences of Schizosaccharomyces pombe subtelomeres reveal multiple patterns of genome variation

2020 ◽  
Author(s):  
Takuto Kaji ◽  
Yusuke Oizumi ◽  
Sanki Tashiro ◽  
Yumiko Takeshita ◽  
Junko Kanoh

AbstractGenome sequences have been determined for many model organisms; however, repetitive regions such as centromeres, telomeres, and subtelomeres have not yet been sequenced completely. Here, we report the complete sequences of subtelomeric homologous (SH) regions of the fission yeast Schizosaccharomyces pombe. We overcame technical difficulties to obtain subtelomeric repetitive sequences by constructing strains that possess single SH regions. Whole sequences of SH regions revealed that each SH region consists of two distinct parts: the telomere-proximal part with mosaics of multiple common segments showing high variation among subtelomeres and strains, and the telomere-distal part showing high sequence similarity among subtelomeres with some insertions and deletions. The newly sequenced SH regions showed differences in nucleotide sequences and common segment composition compared to those in the S. pombe genome database (PomBase), which is in striking contrast to the regions outside of SH, where mutations are rarely detected. Furthermore, we identified new subtelomeric RecQ-type helicase genes, tlh3 and tlh4, which add to the already known tlh1 and tlh2, and found that the tlh1–4 genes show high sequence variation. Our results indicate that SH sequences are highly polymorphic and hot spots for genome variation. These features of subtelomeres may have contributed to genome diversity and, conversely, various diseases.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yusuke Oizumi ◽  
Takuto Kaji ◽  
Sanki Tashiro ◽  
Yumiko Takeshita ◽  
Yuko Date ◽  
...  

AbstractGenome sequences have been determined for many model organisms; however, repetitive regions such as centromeres, telomeres, and subtelomeres have not yet been sequenced completely. Here, we report the complete sequences of subtelomeric homologous (SH) regions of the fission yeast Schizosaccharomyces pombe. We overcame technical difficulties to obtain subtelomeric repetitive sequences by constructing strains that possess single SH regions of a standard laboratory strain. In addition, some natural isolates of S. pombe were analyzed using previous sequencing data. Whole sequences of SH regions revealed that each SH region consists of two distinct parts with mosaics of multiple common segments or blocks showing high variation among subtelomeres and strains. Subtelomere regions show relatively high frequency of nucleotide variations among strains compared with the other chromosomal regions. Furthermore, we identified subtelomeric RecQ-type helicase genes, tlh3 and tlh4, which add to the already known tlh1 and tlh2, and found that the tlh1–4 genes show high sequence variation with missense mutations, insertions, and deletions but no severe effects on their RNA expression. Our results indicate that SH sequences are highly polymorphic and hot spots for genome variation. These features of subtelomeres may have contributed to genome diversity and, conversely, various diseases.


1994 ◽  
Vol 14 (1) ◽  
pp. 576-586 ◽  
Author(s):  
I Roussou ◽  
G Draetta

Casein kinase II is a key regulatory enzyme involved in many cellular processes, including the control of growth and cell division. We report the molecular cloning and sequencing of cDNAs encoding the alpha and the beta subunits of casein kinase II of Schizosaccharomyces pombe. The deduced amino acid sequence of Cka1, the alpha catalytic subunit, shows high sequence similarity to alpha subunits identified in other species. The amino acid sequence of Ckb1, the S. pombe beta subunit, is 57% identical to that of the human beta subunit. Cka1 overexpression results in no detectable phenotype. In contrast, Ckb1 overexpression inhibits cell growth and cytokinesis, with formation of multiseptated cells. Disruption of the ckb1+ gene causes a cold-sensitive phenotype and abnormalities in cell shape. In these cells, the casein kinase II activity is reduced to undetectable levels, demonstrating that Ckb1 is required for enzyme activity in vivo. In agreement with this, the activity measured in a strain expressing high levels of Cka1 is enhanced only when the Ckb1 protein is coexpressed. Altogether, our data suggest that Ckb1 is a positive regulator of the enzyme activity, and that it plays a role in mediating the interaction of casein kinase II with downstream targets and/or with additional regulators.


2021 ◽  
Author(s):  
M. L. Kaldunski ◽  
J. R. Smith ◽  
G. T. Hayman ◽  
K. Brodie ◽  
J. L. De Pons ◽  
...  

AbstractModel organism research is essential for discovering the mechanisms of human diseases by defining biologically meaningful gene to disease relationships. The Rat Genome Database (RGD, (https://rgd.mcw.edu)) is a cross-species knowledgebase and the premier online resource for rat genetic and physiologic data. This rich resource is enhanced by the inclusion and integration of comparative data for human and mouse, as well as other human disease models including chinchilla, dog, bonobo, pig, 13-lined ground squirrel, green monkey, and naked mole-rat. Functional information has been added to records via the assignment of annotations based on sequence similarity to human, rat, and mouse genes. RGD has also imported well-supported cross-species data from external resources. To enable use of these data, RGD has developed a robust infrastructure of standardized ontologies, data formats, and disease- and species-centric portals, complemented with a suite of innovative tools for discovery and analysis. Using examples of single-gene and polygenic human diseases, we illustrate how data from multiple species can help to identify or confirm a gene as involved in a disease and to identify model organisms that can be studied to understand the pathophysiology of a gene or pathway. The ultimate aim of this report is to demonstrate the utility of RGD not only as the core resource for the rat research community but also as a source of bioinformatic tools to support a wider audience, empowering the search for appropriate models for human afflictions.


1994 ◽  
Vol 14 (1) ◽  
pp. 576-586
Author(s):  
I Roussou ◽  
G Draetta

Casein kinase II is a key regulatory enzyme involved in many cellular processes, including the control of growth and cell division. We report the molecular cloning and sequencing of cDNAs encoding the alpha and the beta subunits of casein kinase II of Schizosaccharomyces pombe. The deduced amino acid sequence of Cka1, the alpha catalytic subunit, shows high sequence similarity to alpha subunits identified in other species. The amino acid sequence of Ckb1, the S. pombe beta subunit, is 57% identical to that of the human beta subunit. Cka1 overexpression results in no detectable phenotype. In contrast, Ckb1 overexpression inhibits cell growth and cytokinesis, with formation of multiseptated cells. Disruption of the ckb1+ gene causes a cold-sensitive phenotype and abnormalities in cell shape. In these cells, the casein kinase II activity is reduced to undetectable levels, demonstrating that Ckb1 is required for enzyme activity in vivo. In agreement with this, the activity measured in a strain expressing high levels of Cka1 is enhanced only when the Ckb1 protein is coexpressed. Altogether, our data suggest that Ckb1 is a positive regulator of the enzyme activity, and that it plays a role in mediating the interaction of casein kinase II with downstream targets and/or with additional regulators.


Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Mohamed Ramadan ◽  
Muna Alariqi ◽  
Yizan Ma ◽  
Yanlong Li ◽  
Zhenping Liu ◽  
...  

Abstract Background Upland cotton (Gossypium hirsutum), harboring a complex allotetraploid genome, consists of A and D sub-genomes. Every gene has multiple copies with high sequence similarity that makes genetic, genomic and functional analyses extremely challenging. The recent accessibility of CRISPR/Cas9 tool provides the ability to modify targeted locus efficiently in various complicated plant genomes. However, current cotton transformation method targeting one gene requires a complicated, long and laborious regeneration process. Hence, optimizing strategy that targeting multiple genes is of great value in cotton functional genomics and genetic engineering. Results To target multiple genes in a single experiment, 112 plant development-related genes were knocked out via optimized CRISPR/Cas9 system. We optimized the key steps of pooled sgRNAs assembly method by which 116 sgRNAs pooled together into 4 groups (each group consisted of 29 sgRNAs). Each group of sgRNAs was compiled in one PCR reaction which subsequently went through one round of vector construction, transformation, sgRNAs identification and also one round of genetic transformation. Through the genetic transformation mediated Agrobacterium, we successfully generated more than 800 plants. For mutants identification, Next Generation Sequencing technology has been used and results showed that all generated plants were positive and all targeted genes were covered. Interestingly, among all the transgenic plants, 85% harbored a single sgRNA insertion, 9% two insertions, 3% three different sgRNAs insertions, 2.5% mutated sgRNAs. These plants with different targeted sgRNAs exhibited numerous combinations of phenotypes in plant flowering tissues. Conclusion All targeted genes were successfully edited with high specificity. Our pooled sgRNAs assembly offers a simple, fast and efficient method/strategy to target multiple genes in one time and surely accelerated the study of genes function in cotton.


Author(s):  
Angélique Buton ◽  
Louis-Marie Bobay

Abstract Homologous recombination is a key pathway found in nearly all bacterial taxa. The recombination complex allows bacteria to repair DNA double strand breaks but also promotes adaption through the exchange of DNA between cells. In Proteobacteria, this process is mediated by the RecBCD complex, which relies on the recognition of a DNA motif named Chi to initiate recombination. The Chi motif has been characterized in Escherichia coli and analogous sequences have been found in several other species from diverse families, suggesting that this mode of action is widespread across bacteria. However, the sequences of Chi-like motifs are known for only five bacterial species: E. coli, Haemophilus influenzae, Bacillus subtilis, Lactococcus lactis and Staphylococcus aureus. In this study we detected putative Chi motifs in a large dataset of Proteobacteria and we identified four additional motifs sharing high sequence similarity and similar properties to the Chi motif of E. coli in 85 species of Proteobacteria. Most Chi motifs were detected in Enterobacteriaceae and this motif appears well conserved in this family. However, we did not detect Chi motifs for the majority of Proteobacteria, suggesting that different motifs are used in these species. Altogether these results substantially expand our knowledge on the evolution of Chi motifs and on the recombination process in bacteria.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 947-957 ◽  
Author(s):  
John G Jelesko ◽  
Kristy Carter ◽  
Whitney Thompson ◽  
Yuki Kinoshita ◽  
Wilhelm Gruissem

Abstract Paralogous genes organized as a gene cluster can rapidly evolve by recombination between misaligned paralogs during meiosis, leading to duplications, deletions, and novel chimeric genes. To model unequal recombination within a specific gene cluster, we utilized a synthetic RBCSB gene cluster to isolate recombinant chimeric genes resulting from meiotic recombination between paralogous genes on sister chromatids. Several F1 populations hemizygous for the synthRBCSB1 gene cluster gave rise to Luc+ F2 plants at frequencies ranging from 1 to 3 × 10-6. A nonuniform distribution of recombination resolution sites resulted in the biased formation of recombinant RBCS3B/1B::LUC genes with nonchimeric exons. The positioning of approximately half of the mapped resolution sites was effectively modeled by the fractional length of identical DNA sequences. In contrast, the other mapped resolution sites fit an alternative model in which recombination resolution was stimulated by an abrupt transition from a region of relatively high sequence similarity to a region of low sequence similarity. Thus, unequal recombination between paralogous RBCSB genes on sister chromatids created an allelic series of novel chimeric genes that effectively resulted in the diversification rather than the homogenization of the synthRBCSB1 gene cluster.


Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1692
Author(s):  
Li Gu ◽  
Ting Su ◽  
Ming-Tai An ◽  
Guo-Xiong Hu

Oreocharis esquirolii, a member of Gesneriaceae, is known as Thamnocharis esquirolii, which has been regarded a synonym of the former. The species is endemic to Guizhou, southwestern China, and is evaluated as vulnerable (VU) under the International Union for Conservation of Nature (IUCN) criteria. Until now, the sequence and genome information of O. esquirolii remains unknown. In this study, we assembled and characterized the complete chloroplast (cp) genome of O. esquirolii using Illumina sequencing data for the first time. The total length of the cp genome was 154,069 bp with a typical quadripartite structure consisting of a pair of inverted repeats (IRs) of 25,392 bp separated by a large single copy region (LSC) of 85,156 bp and a small single copy region (SSC) of18,129 bp. The genome comprised 114 unique genes with 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Thirty-one repeat sequences and 74 simple sequence repeats (SSRs) were identified. Genome alignment across five plastid genomes of Gesneriaceae indicated a high sequence similarity. Four highly variable sites (rps16-trnQ, trnS-trnG, ndhF-rpl32, and ycf 1) were identified. Phylogenetic analysis indicated that O. esquirolii grouped together with O. mileensis, supporting resurrection of the name Oreocharis esquirolii from Thamnocharisesquirolii. The complete cp genome sequence will contribute to further studies in molecular identification, genetic diversity, and phylogeny.


2016 ◽  
Vol 198 (9) ◽  
pp. 1393-1400 ◽  
Author(s):  
Guangyu E. Chen ◽  
Andrew Hitchcock ◽  
Philip J. Jackson ◽  
Roy R. Chaudhuri ◽  
Mark J. Dickman ◽  
...  

ABSTRACTThe major photopigment of the cyanobacteriumAcaryochloris marinais chlorophylld, while its direct biosynthetic precursor, chlorophylla, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic phototrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosynthesis. Two unrelated classes of 8-vinyl reductase involved in the biosynthesis of chlorophylls are known to exist, BciA and BciB. The genome ofAcaryochloris marinacontains open reading frames (ORFs) encoding proteins displaying high sequence similarity to BciA or BciB, although they are annotated as genes involved in transcriptional control (nmrA) and methanogenesis (frhB), respectively. These genes were introduced into an 8-vinyl chlorophylla-producing ΔbciBstrain ofSynechocystissp. strain PCC 6803, and both were shown to restore synthesis of the pigment with an ethyl group at C-8, demonstrating their activities as 8-vinyl reductases. We propose thatnmrAandfrhBbe reassigned asbciAandbciB, respectively; transcript and proteomic analysis ofAcaryochloris marinareveal that bothbciAandbciBare expressed and their encoded proteins are present in the cell, possibly in order to ensure that all synthesized chlorophyll pigment carries an ethyl group at C-8. Potential reasons for the presence of two 8-vinyl reductases in this strain, which is unique for cyanobacteria, are discussed.IMPORTANCEThe cyanobacteriumAcaryochloris marinais the best-studied phototrophic organism that uses chlorophylldfor photosynthesis. Unique among cyanobacteria sequenced to date, its genome contains ORFs encoding two unrelated enzymes that catalyze the reduction of the C-8 vinyl group of a precursor molecule to an ethyl group. Carrying a reduced C-8 group may be of particular importance to organisms containing chlorophylld. Plant genomes also contain orthologs of both of these genes; thus, the bacterial progenitor of the chloroplast may also have contained bothbciAandbciB.


2007 ◽  
Vol 57 (6) ◽  
pp. 1243-1249 ◽  
Author(s):  
Ngoc-Phuc Hua ◽  
Atsuko Kanekiyo ◽  
Katsunori Fujikura ◽  
Hisato Yasuda ◽  
Takeshi Naganuma

Two Gram-positive, rod-shaped, moderately halophilic bacteria were isolated from a deep-sea carbonate rock at a methane cold seep in Kuroshima Knoll, Japan. These bacteria, strains IS-Hb4T and IS-Hb7T, were spore-forming and non-motile. They were able to grow at temperatures as low as 9 °C and hydrostatic pressures up to 30 MPa. Based on high sequence similarity of their 16S rRNA genes to those of type strains of the genus Halobacillus, from 96.4 % (strain IS-Hb7T to Halobacillus halophilus NCIMB 9251T) to 99.4 % (strain IS-Hb4T to Halobacillus dabanensis D-8T), the strains were shown to belong to this genus. DNA–DNA relatedness values of 49.5 % and 1.0–33.0 %, respectively, were determined between strains IS-Hb4T and IS-Hb7T and between these strains and other Halobacillus type strains. Both strains showed the major menaquinone MK7 and l-orn–d-Asp cell-wall peptidoglycan type. Straight-chain C16 : 0, unsaturated C16 : 1 ω7c alcohol and C18 : 1 ω7c and cyclopropane C19 : 0 cyc fatty acids were predominant in both strains. The DNA G+C contents of IS-Hb4T and IS-Hb7T were respectively 43.3 and 42.1 mol%. Physiological and biochemical analyses combined with DNA–DNA hybridization results allowed us to place strains IS-Hb4T (=JCM 14154T=DSM 18394T) and IS-Hb7T (=JCM 14155T=DSM 18393T) in the genus Halobacillus as the respective type strains of the novel species Halobacillus profundi sp. nov. and Halobacillus kuroshimensis sp. nov.


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