Transposable Element

(also known as a transposon)

A DNA sequence that can move from one section of the genome to another, affecting chromosome shape and structure as well as gene expression.

  1. Cut-and-paste transposons move by excision from their original location and insertion into a new location, catalyzed by a transposase enzyme encoded by the transposon itself.
  2. Replicative transposons are replicated and the copy is inserted at a new location without loss of the transposon at the original location; this is also catalyzed by a transposase enzyme encoded by the transposon.
  3. Retrotransposons move via RNA transcription of the transposon followed by reverse transcription of the RNA molecule and insertion of the newly synthesized DNA.


An exosome is a small (diameter between 30 and 100nm) extracellular vesicle involved in intercellular communications. Exosomes contain protein, mRNA, miRNA, and dsDNA; they can transfer this cargo from one cell to another, influencing the immune system and activating the organism’s responses to events such as wounds. They have been harnessed by tumors for potential metastatic activity and by researchers for localized tumor-specific drug delivery.


(formalin-fixed, paraffin-embedded)

  • A method for preserving tissue samples
    • Can be stored at room temperature
    • Useful for immunohistochemical assays
    • Tends to degrade RNA, DNA, and proteins; not ideal for molecular analyses
  • Ubiquitous; samples can be obtained from biobanks for future studies