Definitions and Key Features​

 

​Conventional KI mice​ involve the insertion of an exogenous gene into an arbitrary genomic location, which may occur via random integration or through simple homologous recombination targeting a specific locus.
 

​Rosa26 KI mice​ refer to the targeted insertion of an exogenous gene into the Rosa26 locus on mouse chromosome 6. This locus is a highly conserved non-coding genomic region that is broadly active across all cell types and developmental stages. Its promoter exhibits strong transcriptional activity, and its intron contains a unique transcription start site (ATG), enabling stable and reproducible expression of the inserted gene.
 

Key features of Rosa26:

 

A highly conserved non-coding region, minimizing disruption to normal cellular function upon insertion.

An open chromatin structure that supports widespread expression of the transgene (e.g., in whole-body expression tool models).
 

​H11 KI mice​ involve insertion into the H11 locus on mouse chromosome 11, located near the immunoglobulin kappa light chain gene cluster. This region features natively open chromatin, is compatible with diverse promoters, and supports strong expression of exogenous genes across multiple tissues with low immunogenicity, making it particularly suitable for heterologous protein expression.
 

Key features of H11:

 

Proximity to the immunoglobulin κ light chain locus, offering an open chromatin environment compatible with various promoters.
 

Supports high-level transgene expression in multiple tissues (e.g., muscle, liver).
 

​Application Scenarios​

 

​Ubiquitous Expression: Both Rosa26 and H11 KI mice enable whole-body expression. For instance, Rosa26 KI mice can be used to drive transgene expression in all tissues and cell types (e.g., fluorescent protein labeling), while H11 KI mice are suitable for systemic expression such as humanized antibodies. In contrast, conventional KI may yield unstable expression due to unpredictable insertion sites.
 

​Conditional Knock‑In: Rosa26 KI models can be combined with the Cre-loxP system to achieve spatiotemporal or cell-type-specific control of gene expression, allowing flexible conditional genetic manipulation. H11 KI is generally not used for conditional knock-in strategies, and conventional KI would require additional design (e.g., incorporation of LoxP sites) to enable conditional regulation.
 

​High-Level Expression Needs: Owing to its low immunogenicity and favorable genomic context, the H11 site is well-suited for protein overexpression. Rosa26 may be subject to endogenous regulatory constraints, limiting very high expression levels. Although conventional KI can achieve strong expression, it often requires additional promoter optimization and can be less predictable.
 

​Minimizing Insertional Mutagenesis Risk: Both Rosa26 and H11 are intergenic loci with no essential host genes, substantially reducing the risk of disrupting critical genomic functions upon insertion. Conventional KI, being often random, carries a higher risk of insertional mutagenesis by potentially interrupting endogenous genes.