Retroposon
Encyclopedia
Retroposons are repetitive DNA
fragments which are inserted into chromosome
s after they had been reverse transcribed from any RNA
molecule. In contrast to retrotransposon
s, they never encode Reverse Transcriptase
(RT). Therefore, they are non-autonomous elements with regard to transposition activity. (compare Transposon
s)
Non-LTR
retrotransposons (such as the human L1 elements) are sometimes falsely referred to as retroposons.
Retroposition accounts for approximately 10,000 gene-duplication events in the human genome, of which approximately 10% are functional. Such genes are called retrogenes and represent a certain type of retroposons. A classical event is the retroposition of a spliced pre-mRNA molecule of the c-src gene into the proviral ancestor of the Rous Sarcoma Virus (RSV). The retroposed c-src pre-mRNA still contained a single intron
and within RSV is now referred to as v-src gene.
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...
fragments which are inserted into chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s after they had been reverse transcribed from any RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
molecule. In contrast to retrotransposon
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...
s, they never encode Reverse Transcriptase
Reverse transcriptase
In the fields of molecular biology and biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzyme that transcribes single-stranded RNA into single-stranded DNA. It also helps in the formation of a double helix DNA once the RNA has been reverse...
(RT). Therefore, they are non-autonomous elements with regard to transposition activity. (compare Transposon
Transposon
Transposable elements are sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell. The mechanism of transposition can be either "copy and paste" or "cut and paste". Transposition can create phenotypically significant mutations and alter the cell's...
s)
Non-LTR
Long terminal repeat
Long terminal repeats are sequences of DNA that repeat hundreds or thousands of times. They are found in retroviral DNA and in retrotransposons, flanking functional genes...
retrotransposons (such as the human L1 elements) are sometimes falsely referred to as retroposons.
Retroposition accounts for approximately 10,000 gene-duplication events in the human genome, of which approximately 10% are functional. Such genes are called retrogenes and represent a certain type of retroposons. A classical event is the retroposition of a spliced pre-mRNA molecule of the c-src gene into the proviral ancestor of the Rous Sarcoma Virus (RSV). The retroposed c-src pre-mRNA still contained a single intron
Intron
An intron is any nucleotide sequence within a gene that is removed by RNA splicing to generate the final mature RNA product of a gene. The term intron refers to both the DNA sequence within a gene, and the corresponding sequence in RNA transcripts. Sequences that are joined together in the final...
and within RSV is now referred to as v-src gene.