scholarly journals Mechanisms of gene rearrangement in 13 bothids based on comparison with a newly completed mitogenome of the threespot flounder, Grammatobothus polyophthalmus (Pleuronectiformes: Bothidae)

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Hairong Luo ◽  
Xiaoyu Kong ◽  
Shixi Chen ◽  
Wei Shi

Abstract Background The mitogenomes of 12 teleost fish of the bothid family (order Pleuronectiformes) indicated that the genomic-scale rearrangements characterized in previous work. A novel mechanism of genomic rearrangement called the Dimer-Mitogenome and Non-Random Loss (DMNL) model was used to account for the rearrangement found in one of these bothids, Crossorhombus azureus. Results The 18,170 bp mitogenome of G. polyophthalmus contains 37 genes, two control regions (CRs), and the origin of replication of the L-strand (OL). This mitogenome is characterized by genomic-scale rearrangements: genes located on the L-strand are grouped in an 8-gene cluster (Q-A-C-Y-S1-ND6-E-P) that does not include tRNA-N; genes found on the H-strand are grouped together (F-12S … CytB-T) except for tRNA-D that was translocated inside the 8-gene L-strand cluster. Compared to non-rearranged mitogenomes of teleost fishes, gene organization in the mitogenome of G. polyophthalmus and in that of the other 12 bothids characterized thus far is very similar. These rearrangements could be sorted into four types (Type I, II, III and IV), differing in the particular combination of the CR, tRNA-D gene and 8-gene cluster and the shuffling of tRNA-V. The DMNL model was used to account for all but one gene rearrangement found in all 13 bothid mitogenomes. Translocation of tRNA-D most likely occurred after the DMNL process in 10 bothid mitogenomes and could have occurred either before or after DMNL in the three other species. During the DMNL process, the tRNA-N gene was retained rather than the expected tRNA-N′ gene. tRNA-N appears to assist in or act as OL function when the OL secondary structure could not be formed from intergenic sequences. A striking finding was that each of the non-transcribed genes has degenerated to a shorter intergenic spacer during the DMNL process. These findings highlight a rare phenomenon in teleost fish. Conclusions This result provides significant evidence to support the existence of dynamic dimeric mitogenomes and the DMNL model as the mechanism of gene rearrangement in bothid mitogenomes, which not only promotes the understanding of mitogenome structural diversity, but also sheds light on mechanisms of mitochondrial genome rearrangement and replication.

2019 ◽  
Author(s):  
Hairong Luo ◽  
Xiaoyu Kong ◽  
Shixi Chen ◽  
Wei Shi

Abstract Background: The previously characterized mitogenomes of 12 teleost fish of the bothid family (order Pleuronectiformes) indicated that the genomic-scale rearrangements occurred in this teleost lineage. A novel mechanism of genomic rearrangement called the Dimer-Mitogenome and Non-Random Loss (DMNL) model was used to account for the rearrangement found in one of these bothids, Crossorhombus azureus. Results: The 18170 bp mitogenome of G. polyophthalmus contains 37 genes, two control regions (CRs), and the origin of replication of the L-strand (OL). This mitogenome is characterized by genomic-scale rearrangements: genes located on the L-strand are grouped in an 8-gene cluster (Q-A-C-Y-S1-ND6-E-P) that does not include tRNA-N; genes found on the H-strand are grouped together (F-12S … CytB-T) except for tRNA-D that was translocated inside the 8-gene L-strand cluster. Compared to non-rearranged mitogenomes of teleost fishes, gene organization in the mitogenome of G. polyophthalmus and in that of the other 12 bothids characterized thus far is very similar. These rearrangements could be sorted into four types (Type I, II, III and IV), differing in the particular combination of the CR, tRNA-D gene and 8-gene cluster and the shuffling of tRNA-V. The DMNL model was used to account for all but one gene rearrangement found in all 13 bothid mitogenomes. Translocation of tRNA-D most likely occurred after the DMNL process in 10 bothid mitogenomes and could have occurred either before or after DMNL in the three other species. During the DMNL process, the tRNA-N gene was retained rather than the expected tRNA-N′ gene. tRNA-N appears to assist in or act as OL function when the OL secondary structure could not be formed from intergenic sequences. A striking finding was that each of the non-transcribed genes has degenerated to a shorter intergenic spacer during the DMNL process. These findings highlight a rare phenomenon in teleost fish. Conclusions: This result provides significant evidence to support the existence of dynamic dimeric mitogenomes and the DMNL model as the mechanism of gene rearrangement in bothid mitogenomes, which not only promotes the understanding of mitogenome structural diversity, but also sheds light on mechanisms of mitochondrial genome rearrangement and replication.


2019 ◽  
Author(s):  
Hairong Luo ◽  
Xiaoyu Kong ◽  
Shixi Chen ◽  
Wei Shi

Abstract Background: The previously characterized mitogenomes of 12 teleost fish of the bothid family (order Pleuronectiformes) indicated that the genomic-scale rearrangements occurred in this teleost lineage. A novel mechanism of genomic rearrangement called the Dimer-Mitogenome and Non-Random Loss (DMNL) model was used to account for the rearrangement found in one of these bothids, Crossorhombus azureus. Results: The 18170 bp mitogenome of G. polyophthalmus contains 37 genes, two control regions (CRs), and the origin of replication of the L-strand (OL). This mitogenome is characterized by genomic-scale rearrangements: genes located on the L-strand are grouped in an 8-gene cluster (Q-A-C-Y-S1-ND6-E-P) that does not include tRNA-N; genes found on the H-strand are grouped together (F-12S … CytB-T) except for tRNA-D that was translocated inside the 8-gene L-strand cluster. Compared to non-rearranged mitogenomes of teleost fishes, gene organization in the mitogenome of G. polyophthalmus and in that of the other 12 bothids characterized thus far is very similar. These rearrangements could be sorted into four types (Type I, II, III and IV), differing in the particular combination of the CR, tRNA-D gene and 8-gene cluster and the shuffling of tRNA-V. The DMNL model was used to account for all but one gene rearrangement found in all 13 bothid mitogenomes. Translocation of tRNA-D most likely occurred after the DMNL process in 10 bothid mitogenomes and could have occurred either before or after DMNL in the three other species. During the DMNL process, the tRNA-N gene was retained rather than the expected tRNA-N′ gene. tRNA-N appears to assist in or act as OL function when the OL secondary structure could not be formed from intergenic sequences. A striking finding was that each of the non-transcribed genes has degenerated to a shorter intergenic spacer during the DMNL process. These findings highlight a rare phenomenon in teleost fish. Conclusions: This result provides significant evidence to support the existence of dynamic dimeric mitogenomes and the DMNL model as the mechanism of gene rearrangement in bothid mitogenomes, which not only promotes the understanding of mitogenome structural diversity, but also sheds light on mechanisms of mitochondrial genome rearrangement and replication.


2019 ◽  
Author(s):  
Hairong Luo ◽  
Xiaoyu Kong ◽  
Shixi Chen ◽  
Wei Shi

Abstract Background: The mitochondrial genomes (mitogenomes) of 12 bothids (Pleuronectiformes) from eight genera have been obtained. From the data, the genomic-scale and various gene rearrangements revealed the high diversity of variation in these mitogenomes. Results: A total of 18170 bp of Grammatobothus polyophthalmus mitogenome was determined including 37 genes and two control regions (CRs). Genes encoded by L-strand were grouped to an eight-genes cluster (Q-A-C-Y-S1-ND6-E-P) except for the tRNA-N, other genes encoded by H-strand were grouped together (F-12S … CytB-T) except for the tRNA-D that was translocated to inside of the eight-genes cluster. The mitogenome of G. polyophthalmus and that of 12 known bothids possessed the similar genomic-scale rearrangements with the only differences in the various combinations of CR, tRNA-D and eight-genes cluster, and the shuffling of tRNA-V. Based on the structure character of all 13 bothid mitogenomes, the Dimer-Mitogenome and Non-Random Loss (DMNR) model was fitted to account for all these rearrangements. And the translocation of tRNA-D occurring after the DMNR process in 10 of 13 bothid mitogenomes was confirmed. The striking finding was that each of degenerated genes existing in the gene rearrangement process in 13 bothids had their counterparts of intergenic spaces. Conclusions: The result of corresponding relationship between degenerated genes and intergenic spaces provided the significant evidence to support the possibility of the DMNR model, as well as, the existing of dimeric mitogenome in mitochondrion. The findings of this study were rare phenomenona in teleost fish, which not only promoted the understanding of mitogenome structural diversity, but also shed light on studying of mitochondrial rearrangement and replication.


2021 ◽  
Vol 85 (3) ◽  
pp. 714-721
Author(s):  
Risa Takao ◽  
Katsuyuki Sakai ◽  
Hiroyuki Koshino ◽  
Hiroyuki Osada ◽  
Shunji Takahashi

ABSTRACT Recent advances in genome sequencing have revealed a variety of secondary metabolite biosynthetic gene clusters in actinomycetes. Understanding the biosynthetic mechanism controlling secondary metabolite production is important for utilizing these gene clusters. In this study, we focused on the kinanthraquinone biosynthetic gene cluster, which has not been identified yet in Streptomyces sp. SN-593. Based on chemical structure, 5 type II polyketide synthase gene clusters were listed from the genome sequence of Streptomyces sp. SN-593. Among them, a candidate gene cluster was selected by comparing the gene organization with grincamycin, which is synthesized through an intermediate similar to kinanthraquinone. We initially utilized a BAC library for subcloning the kiq gene cluster, performed heterologous expression in Streptomyces lividans TK23, and identified the production of kinanthraquinone and kinanthraquinone B. We also found that heterologous expression of kiqA, which belongs to the DNA-binding response regulator OmpR family, dramatically enhanced the production of kinanthraquinones.


1995 ◽  
Vol 15 (5) ◽  
pp. 2367-2373 ◽  
Author(s):  
N Armes ◽  
M Fried

The Surf-3 gene of the unusually tight mouse Surfeit locus gene cluster has been identified as the highly conserved ribosomal protein gene L7a (rpL7a). The topography and juxtaposition of the Surfeit locus genes are conserved for the 600 million years of divergent evolution between mammals and birds. This suggests cis interaction and/or coregulation of the genes and suggests that, within this locus, gene organization plays an important role in gene expression. The further evolutionary conservation of the organization of the Surfeit locus was investigated. A cDNA encoding the Drosophila melanogaster homolog of the Surf-3/rpL7a gene was cloned, was shown to be present as a single copy, and was expressed constitutively at high levels throughout development. Genomic cosmid clones encompassing the gene and its surrounding DNA were isolated. The gene was determined to have five introns, of which two were located in the 5' untranslated region of the gene. The remaining three introns had splice sites at positions equivalent to those found in the Surf-3/rpL7a mammalian homologs. S1 analysis and 5' rapid amplification of cDNA ends both confirmed the start of transcription to occur in a polypyrimidine tract in the absence of a TATA box in the promoter. The genomic region around the Surf-3/rpL7a gene was analyzed by low-stringency hybridization with murine Surfeit gene probes, by partial sequence analysis, and by hybridization of fragments to Northern (RNA) blots. No homologs of other members of the Surfeit gene cluster were detected in close proximity to the D. melanogaster Surf-3/rpL7a gene. However, a gene which was detected directly 3' to the Surf-3/rpL7a gene was shown to encode a homolog of a mammalian serine-pyruvate aminotransferase.


2013 ◽  
Vol 35 (4) ◽  
pp. 1176-1184 ◽  
Author(s):  
Bokwang Kim ◽  
Meesun Kim ◽  
Ah Ran Kim ◽  
Myunggi Yi ◽  
Jung-Hwa Choi ◽  
...  
Keyword(s):  
Type I ◽  

2019 ◽  
Author(s):  
Trevor Kane ◽  
Katelyn E. Carothers ◽  
Yunjuan Bao ◽  
Won-Sik Yeo ◽  
Taeok Bae ◽  
...  

AbstractBackgroundStaphylococcus aureus (S. aureus) is a major human pathogen owing to its arsenal of virulence factors, as well as its acquisition of multi-antibiotic resistance. Here we report the identification of a Streptolysin S (SLS) like biosynthetic gene cluster in a highly virulent community-acquired methicillin resistant S. aureus (MRSA) isolate, JKD6159. Examination of the SLS-like gene cluster in JKD6159 shows significant homology and gene organization to the SLS-associated biosynthetic gene (sag) cluster responsible for the production of the major hemolysin SLS in Group A Streptococcus.ResultsWe took a comprehensive approach to elucidating the putative role of the sag gene cluster in JKD6159 by constructing a mutant in which one of the biosynthesis genes (sagB homologue) was deleted in the parent JKD6159 strain. Assays to evaluate bacterial gene regulation, biofilm formation, antimicrobial activity, as well as complete host cell response profile and comparative in vivo infections in Balb/Cj mice were conducted.ConclusionsAlthough no significant phenotypic changes were observed in our assays, we postulate that the SLS-like toxin produced by this strain of S. aureus may be a highly specialized virulence factor utilized in specific environments for selective advantage; studies to better understand the role of this newly discovered virulence factor in S. aureus warrant further investigation.


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