Transposon

From Anvita Health Wiki

Contents 1 More Specific Terms 2 Introduction 3 Pathology 4 Physiology 5 More General Terms 6 Additional Terms 7 References

More Specific Terms

• DNA transposon (class 2 transposon)
• retrotransposon (class 1 transposon)

Introduction

• Sequence of mobile DNA able to move to different positions within the genome of a single cell ( transposition). In the process of transposition, they may cause mutations &/or change the amount of DNA in the genome. Found in all major branches of life.

• May be grouped based on their mechanism of transposition:

• retrotransposons (class 1) .- DNA transposons (class 2)

• The most common form of transposon in humans is the Alu sequence

Pathology

• transposons are mutagens
• they can damage the genome of their host cell:

• a transposon or a retroposon that inserts itself into a functional gene will most likely disable that gene
• after a transposon leaves a gene, the resulting gap will probably not be repaired correctly
• multiple copies of the same sequence, such as Alu sequences can hinder precise chromosomal pairing during mitosis, resulting in unequal crossovers, one of the main reasons for chromosome duplication

• diseases often caused by transposons include:

• hemophilia A, hemophilia B
• severe combined immunodeficiency
• porphyria
• Duchenne muscular dystrophy

• transposons may predispose to cancer
• many transposons contain promoters which drive transcription of their own transposase; these promoters can cause aberrant expression of linked genes, causing disease or mutant phenotypes

• Mechanisms adapted for reducing transposon activity include:

• gene deletion
• RNA interference ( RNAi)

• Transposons are used as a research tool to alter DNA inside a living organism. Transposons make up a large fraction of genome sizes of eukaryotic species.

Physiology

• may have provided a means of producing antibody diversity
• V(D)J recombination system operates by a mechanism similar to that of transposons
• evolution of autosomal retrogenes from X-linked progenitors compensates for X-chromosome silencing during male meiosis

More General Terms

• biochemistry

Additional Terms

• gene

References

1. Wikipedia, the free encyclopedia [1]
2. McClintock, B. The origin and behavior of mutable loci in maize. Proc Natl Acad Sci U S A. (1950) 36(6): 344-55. PMID: [2]

transposon (jumping gene, transposable element, mobile genetic element, selfish DNA)