Mobile elements

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Mobile elements

• Introduction
• Discovery
• Bacterial elements
• P elements
• SINEs and LINEs

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Mobile elements

• Discovery
• McClintock Corn Ac (activator) and Ds
  (Dissociation)

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Mobile elements

• Transposition of Ds into the C gene of corn.
• C allows color expression c does not.
• The action of Ds is dependent on the presence of
  the unlinked gene Ac.

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Mobile elements

• Summary of the main effects of controlling
  elements in corn.

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Mobile elements

• Bacterial elements
• Insertion Sequences (IS)
• TN 9

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Mobile elements

• Role of transposons in the evolution of
  antibiotic resistance plasmids.

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Mobile elements

• Tn3
• Transposase, repressor, internal resolution site
  and antibiotic resistance gene
• Transposition through a cointegrate intermediate

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Mobile elements

• Conservative vs. replicative transposition.

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Mobile elements

• Consequences of conservative and replicative
  transposition.

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Mobile elements

• Consequences of the insertion of an IS element

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Mobile elements

• Life cycle of a retrovirus.

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Mobile elements

• Transposition of a retrovirus.

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Mobile elements

• Schematic diagram of a generic viral
  retrotransposon.
• Yeast Ty elements
• Drosophila Copia elements

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Mobile elements

• Demonstration of transposition through an RNA
  intermediate.
• The construct has a Ty element with an intron
  from another gene inserted in it that must be
  spliced out in order to support transposition.

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Mobile elements

• Copia elements
• 5-8.5 kb in size
• 10-100 copies

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Mobile elements

• P element mediated germ line transformation.

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What are SINEs?
1. Interspersed Elements 2. 70 - 300 Bases in
Length 3. Very High Copy Numbers (gt100,000
Copies/Genome)
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What are LINEs?
1. Interspersed Elements 2. gt500 Bases in Length
3. Very High Copy Numbers (gt100,000
Copies/Genome)
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LINE structure
ORF2 (4 kb)
ORF1 (1 kb)
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direct repeats
A/T-rich region and UTR
UTR
Coding region
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L1 Ta Subfamily
1. ACA 3 UTR Sequence at bp 5930 2. Approximatel
y 520 copies 3. Active Elements (44/124 full
length) 4. Several de novo insertions