R2 RNA element
Encyclopedia
The R2 RNA element is a non-long terminal repeat (non-LTR) retrotransposable element
that inserts at a specific site in the 28S ribosomal RNA
(rRNA) genes of most insect genomes. In order to insert itself into the genome, retrotransposon encoded protein
(R2) protein makes a specific nick in one of the DNA
strands at the insertion site and uses the 3′ hydroxyl group exposed by this nick to prime the reverse transcription process termed target primed reverse transcription (TPRT), where the RNA genome is transcribed into DNA.
the reverse transcription process (an essential part of retrotransposon insertion into the host genome
). An RNA fragment found in the R2 3' untranslated region
(3'UTR), has been shown to interact with one copy of R2 protein during TPRT. This fragment has been shown to possess conserved secondary structure within Drosophila
and silk moths, and also between the two groups.
and performs self-splicing. This ribozyme has been found to have high sequence similarity to the HDV ribozyme but they are not homologous; the two sequences are thought to have undergone convergent evolution
.
Retrotransposon
Retrotransposons are genetic elements that can amplify themselves in a genome and are ubiquitous components of the DNA of many eukaryotic organisms. They are a subclass of transposon. They are particularly abundant in plants, where they are often a principal component of nuclear DNA...
that inserts at a specific site in the 28S ribosomal RNA
Ribosomal RNA
Ribosomal ribonucleic acid is the RNA component of the ribosome, the enzyme that is the site of protein synthesis in all living cells. Ribosomal RNA provides a mechanism for decoding mRNA into amino acids and interacts with tRNAs during translation by providing peptidyl transferase activity...
(rRNA) genes of most insect genomes. In order to insert itself into the genome, retrotransposon encoded protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
(R2) protein makes a specific nick in one of the DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
strands at the insertion site and uses the 3′ hydroxyl group exposed by this nick to prime the reverse transcription process termed target primed reverse transcription (TPRT), where the RNA genome is transcribed into DNA.
3' UTR element
The R2 element 3' UTR RNA is a cis-acting element identified in R2 retrotransposons which is involved in primingPrimer (molecular biology)
A primer is a strand of nucleic acid that serves as a starting point for DNA synthesis. They are required for DNA replication because the enzymes that catalyze this process, DNA polymerases, can only add new nucleotides to an existing strand of DNA...
the reverse transcription process (an essential part of retrotransposon insertion into the host genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
). An RNA fragment found in the R2 3' untranslated region
Three prime untranslated region
In molecular genetics, the three prime untranslated region is a particular section of messenger RNA . It is preceeded by the coding region....
(3'UTR), has been shown to interact with one copy of R2 protein during TPRT. This fragment has been shown to possess conserved secondary structure within Drosophila
Drosophila
Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...
and silk moths, and also between the two groups.
5' UTR ribozyme
The 5' UTR of R2 RNA is thought to be capable of acting as a ribozymeRibozyme
A ribozyme is an RNA molecule with a well defined tertiary structure that enables it to catalyze a chemical reaction. Ribozyme means ribonucleic acid enzyme. It may also be called an RNA enzyme or catalytic RNA. Many natural ribozymes catalyze either the hydrolysis of one of their own...
and performs self-splicing. This ribozyme has been found to have high sequence similarity to the HDV ribozyme but they are not homologous; the two sequences are thought to have undergone convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
.