What is Retrohoming?

Group II introns in yeast mitochondria are mobile retroelements, capable of homing into cognate intronless alleles. The RNA-mediated mobility event, termed retrohoming, requires the intron-encoded protein, which has three activities: RNA maturase, DNA endonuclease, and reverse transcriptase (RT).

What is homing and Retrohoming?

This copying of the intron from occupied to unoccupied sites has been called homing. Mobile group II introns, in contrast, encode both a sequence-specific endonuclease and a reverse transcriptase, and their movement, termed retrohoming, has long been suspected to be more like that of retrotransposable elements.

What is intron homing?

INTRODUCTION. Homing is the lateral transfer of an intervening sequence (either an intron or intein) to a homologous allele that lacks the sequence (1). The process is catalyzed by an endonuclease that recognizes and cleaves the target allele.

How do Meganucleases work?

Meganucleases are “molecular DNA scissors” that can be used to replace, eliminate or modify sequences in a highly targeted way. By modifying their recognition sequence through protein engineering, the targeted sequence can be changed.

What does HNH endonuclease do?

HNH endonucleases are present in many bacteriophages and prophages. The location of an HNH endonuclease gene in phage genomes is next to a terminase gene and is highly conserved, suggesting a possible biological role in the stimulation of homologous recombination by nicking DNA, which further enhances gene conversion.

What are genome editing techniques?

Genome editing is a process where an organism’s genetic code is changed. Scientists use enzymes to ‘cut’ DNA creating a double-strand break (DSB). DSB repair occurs by non-homologous end joining (NHEJ) or homology-directed repair (HDR).

What is RuvC and HNH?

All known Cas9 enzymes contain an HNH domain that cleaves the DNA strand complementary to the guide RNA sequence (target strand), and a RuvC nuclease domain required for cleaving the noncomplementary strand (non-target strand), yielding double-strand DNA breaks (DSBs).

How does a zinc atom help stabilize the zinc finger?

The zinc atom is simultaneously bound by the 2 cysteine and the 2 histidine side chains. DNA has a negatively-charged phosphate backbone. Therefore, the positively- charged arginine of the zinc finger can bind to DNA via an electrostatic interaction.

How many gene editing methods are there?

NHEJ produces random mutations (gene knockout), while HDR uses additional DNA to create a desired sequence within the genome (gene knock-in). The four main gene editing techniques, which we will discuss in the following sections, all follow the above-mentioned basic pattern.

How many types of gene editing are there?

Here, we review recent advances of the three major genome editing technologies (ZFNs, TALENs, and CRISPR/Cas9) and discuss the applications of their derivative reagents as gene editing tools in various human diseases and potential future therapies, focusing on eukaryotic cells and animal models.