Complex terminal structure of a linear mitochondrial plasmid from Physarum polycephalum: three terminal inverted repeats and an ORF encoding DNA polymerase

1994 ◽  
Vol 25 (3) ◽  
pp. 252-257 ◽  
Author(s):  
Hiroyoshi Takano ◽  
Shigeyuki Kawano ◽  
Tsuneyoshi Kuroiwa
Keyword(s):  
Dna Polymerase ◽  
Physarum Polycephalum ◽  
Inverted Repeats ◽  
Mitochondrial Plasmid ◽  
Terminal Inverted Repeats ◽  
Linear Mitochondrial Plasmid ◽  
Terminal Structure

Telomeric structures in a linear mitochondrial plasmid from Physarum polycephalum

1991 ◽  
Vol 20 (4) ◽  
pp. 315-317 ◽  
Author(s):  
Hiroyoshi Takano ◽  
Shigeyuki Kawano ◽  
Tsuneyoshi Kuroiwa
Keyword(s):  
Physarum Polycephalum ◽  
Mitochondrial Plasmid ◽  
Linear Mitochondrial Plasmid

Linear plasmids that integrate into mitochondrial DNA in Neurospora

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 155-159 ◽  
Author(s):  
H. Bertrand ◽  
A. J. F. Griffiths
Keyword(s):  
Mitochondrial Dna ◽  
Rna Polymerase ◽  
Dna Polymerase ◽  
Inverted Repeats ◽  
Insertion Sequences ◽  
Long Terminal Repeats ◽  
Linear Plasmids ◽  
Mt Dna ◽  
Common Features ◽  
Mitochondrial Chromosome

In some field isolates of Neurospora from Hawaii and India, senescence is induced by integration of linear DNA plasmids, kalilo and maranhar, respectively, into mitochondrial (mt) DNA. Although the two plasmids show little homology at the DNA level, both have inverted long terminal repeats, and each potentially encodes a DNA polymerase and a RNA polymerase. Both plasmids generate very long inverted repeats of mtDNA at their ends upon integration into mitochondrial chromosomes. Hence, they appear to integrate by a mechanism that involves pairing of both ends of the plasmid with short stretches of homologous nucleotide sequences in mtDNA. This recombinogenic association apparently generates an origin for an unscheduled round of replication of mtDNA. In the process, the resulting two copies of the mitochondrial chromosome are joined to opposite ends of the plasmid. A model for the senescence-associated accumulation of mtDNAs with plasmid insertion sequences is proposed on the basis of common features that characterize senescence in a variety of filamentous fungi.Key words: Neurospora, senescence, plasmids, mitochondria.

scholarly journals Functional requirement of terminal inverted repeats for efficient ProtoRAG activity reveals the early evolution of V(D)J recombination

2019 ◽  
Vol 7 (2) ◽  
pp. 403-417 ◽  
Author(s):  
Xin Tao ◽  
Shaochun Yuan ◽  
Fan Chen ◽  
Xiaoman Gao ◽  
Xinli Wang ◽  
...  
Keyword(s):  
Consensus Sequence ◽  
Protein Stabilization ◽  
Inverted Repeats ◽  
Functional Requirement ◽  
Signal Sequences ◽  
Terminal Inverted Repeats ◽  
Homologous Sequences ◽  
Recombination Signal Sequences ◽  
Chordate Evolution ◽  
The Common

Abstract The discovery of ProtoRAG in amphioxus indicated that vertebrate RAG recombinases originated from an ancient transposon. However, the sequences of ProtoRAG terminal inverted repeats (TIRs) were obviously dissimilar to the consensus sequence of mouse 12/23RSS and recombination mediated by ProtoRAG or RAG made them incompatible with each other. Thus, it is difficult to determine whether or how 12/23RSS persisted in the vertebrate RAG system that evolved from the TIRs of ancient RAG transposons. Here, we found that the activity of ProtoRAG is highly dependent on its asymmetric 5′TIR and 3′TIR, which are composed of conserved TR1 and TR5 elements and a partially conserved TRsp element of 27/31 bp to separate them. Similar to the requirements for the recombination signal sequences (RSSs) of RAG recombinase, the first CAC in TR1, the three dinucleotides in TR5 and the specific length of the partially conserved TRsp are important for the efficient recombination activity of ProtoRAG. In addition, the homologous sequences flanking the signal sequences facilitate ProtoRAG- but not RAG-mediated recombination. In addition to the diverged TIRs, two differentiated functional domains in BbRAG1L were defined to coordinate with the divergence between TIRs and RSSs. One of these is the CTT* domain, which facilitates the specific TIR recognition of the BbRAGL complex, and the other is NBD*, which is responsible for DNA binding and the protein stabilization of the BbRAGL complex. Thus, our findings reveal that the functional requirement for ProtoRAG TIRs is similar to that for RSS in RAG-mediated recombination, which not only supports the common origin of ProtoRAG TIRs and RSSs from the asymmetric TIRs of ancient RAG transposons, but also reveals the development of RAG and RAG-like machineries during chordate evolution.

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