What are the characteristics of the sequence composition of transposons?

Classification and structural characteristics of transposons.

a.Simple transposon.

Transposon (TN) is the basic unit of autonomous replication and translocation on chromosomal DNA.

The simplest transposons do not contain any host genes and are often referred to as insertion sequences (ISs), which are normal components of bacterial chromosomes or plasmid DNA. A bacterial cell often carries less than 10 IS sequences. Transposons are often localized to a specific gene, causing mutations in that gene.

IS sequences are units that can exist independently, with proteins that mediate their own mobility.

b.Composite transposon is a type of transposon with certain drug resistance genes (or other host genes), and its wings are often two identical or highly homologous IS sequences, indicating that compound transposons may be produced when the IS sequence is inserted into both ends of a functional gene. Once a composite transposon is formed, the IS sequence can no longer move alone because their function is modified and can only move as a complex.

I choose BInsert sequence composition: inverted repeat sequence (IR):

Located on both sides, it plays a role in the cleavage of IS and the transfer of DNA strands. Transposase-encoding gene: located in the middle, the product causes transposposition and is responsible for identifying the ends of the transposon and causing a nick at the target site.

Forward repeats: located outside the inverted repeats, unique to insertions. Transposon (TN):

They are more complex transposable factors that contain resistance or other genes in addition to transposase genes. There are two categories: compound transposons:

Inserts with either forward or reverse repeat at both ends serve as the two arms, with the marker gene in the middle. Complex transposon: no insertion sequence at both ends, but inverted repeating sequence.

** is a transposase gene and a drug resistance gene.

The insertion sequence does not contain any host genes, and the composite transposon carries some resistance genes!

Transposons are the basic units of autonomous replication and displacement that exist on chromosomal DNA. The simplest transposons do not contain any host genes and are called insert sequences (ISs), which are normal components of bacterial chromosomes or plasmid DNA. She is often localized to a specific group, causing genetic mutations.

Compound transposon is a kind of transposon with certain drug resistance genes, and its two wings are the same or highly homologous IS sequence, and the IS sequence cannot move alone, but can only move as a complex, and the IS sequence also determines and regulates the transposable ability of the transposon. There is also a transposon DNA family with no IS sequence, with 38 bp inverted repeats on both wings.

Transposable factor. A transposable element is a sequence of deoxyribonucleic acid (DNA) in cells that changes its position. The act of a transposable factor changing position, such as from one location on a chromosome to another, or from a plasmid to a chromosome, is called transposable.

Because the transposable factor can not only bring new genetic material to the genome, but also enable or close certain genes like a switch in some cases, and often cause DNA rearrangements such as deletion, duplication, or inversion of the genome, it is closely related to biological evolution and may be related to ontogeny and cell differentiation.

In addition, the transposposition of transposable factors with different drug resistance genes between bacterial plasmids will lead to the formation of polyvalent resistant plasmids, which will reduce the efficacy of multiple drugs and is a threat to human health, so it is necessary to study solutions. On the other hand, transposable factors with unique functions have become a useful tool in genetic research.