Ming, what's the difference between conventional KI mice and Rosa26/H11 KI mice?

 

First, let's understand the genomic locations of Rosa26 and H11. Rosa26 is located on mouse chromosome 6 (human homologous locus is on chromosome 3p25.3), while H11 is located on mouse chromosome 11 (human homologous locus is on chromosome 17q21.31).

 

Now, let's explore their differences in terms of definition, core characteristics, and application scenarios.

 

Differences Between KI Mice and Rosa26/H11 KI Mice
 

Definition and Core Characteristics
 

Conventional KI Mice:  These involve inserting exogenous genes into arbitrary genomic locations, which may be random integration or rely on simple homologous recombination targeting.
 

Rosa26 KI Mice:  These insert exogenous genes into the Rosa26 locus on mouse chromosome 6. This is a highly conserved non-coding gene locus that exhibits broad expression across all cell types and developmental stages. Its promoter region has high transcriptional activity, and its intron contains unique transcription start sites (ATG), enabling stable, reproducible expression of exogenous genes.
 

Rosa26 Characteristics:
 

1.Highly conserved non-coding region; insertion does not affect cellular function.

2.Open chromatin structure supports broad-spectrum expression of exogenous genes (e.g., whole-body expression in tool mouse models).
 

H11 KI Mice:  These insert exogenous genes into the H11 locus on mouse chromosome 11. This locus is located near the immunoglobulin κ light chain gene locus, with naturally open chromatin that is compatible with various promoters. It supports high expression of exogenous genes in multiple tissues and has low immunogenicity, making it suitable for heterologous protein expression.
 

H11 Characteristics:

1.Located near the immunoglobulin κ light chain gene locus; naturally open chromatin compatible with multiple promoters.

2.Supports high expression of exogenous genes in various tissues (e.g., muscle, liver).
 

Application Scenarios
 

Global Expression:  Both Rosa26 KI mice and H11 KI mice can achieve whole-body expression. For example, Rosa26 KI mice can utilize their broad-spectrum expression characteristics to express exogenous genes in all tissues and cells of the animal body, such as expressing fluorescent proteins to label all cells. H11 KI mice can be used for whole-body expression of humanized antibodies. In contrast, conventional KI mice may have unstable expression due to uncertain insertion sites.
 

Conditional Knock-In:  Rosa26 KI mice can be combined with the Cre system, using the cre-loxp recombination system to achieve temporal and cell-type-specific control of gene expression, enabling flexible conditional gene manipulation. H11 KI mice are typically not used for conditional knock-in. If conventional KI mice are to achieve conditional knock-in, additional LoxP sites need to be designed.
 

High Expression Requirements:  H11 KI mice, with their low immunogenicity and locus advantages, are suitable for protein overexpression. Rosa26 KI mice may be limited by endogenous regulatory elements and may not meet ultra-high expression requirements. Although conventional KI mice can also achieve high expression, optimization of promoters and other elements is needed to enhance expression levels.
 

Avoiding Insertional Mutagenesis Risk:  Both Rosa26 and H11 KI mice have intergenic regions without endogenous genes, so inserting exogenous genes does not disrupt host critical functional genes, reducing the risk of insertional mutagenesis. In contrast, conventional KI mice carry the risk of disrupting genes within the genome due to random insertion.

 

References:

[1]https://www.nature.com/articles/nn.2467

[2]https://www.nature.com/articles/ng0199_70

[3]https://mp.weixin.qq.com/s/-NnpI6_p8Adn4FiqZN9r0g

[4]https://mp.weixin.qq.com/s/XSRoWsaSGSl1ByM4DR4XfA

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