Lbr-flox Mouse

Lbr, short for Lamin B receptor, is a nuclear-membrane protein with sterol reductase activity. It resides in the inner nuclear membrane, providing attachment sites for chromatin and the nuclear lamina, thus being crucial for the functional organization of the nucleus. It is also involved in regulating heterochromatin organization [1,2].

A 236bp N-terminal deletion in the mouse Lbr gene, generated via CRISPR/Cas-9 gene editing, recapitulates human Pelger-Huet anomaly (PHA) phenotypes better than existing models, and shows minor X chromosome inactivation defects without overt in vivo phenotypes. This model provides a valuable tool for understanding PHA etiology [1]. Additionally, knockdown of LBR in human cells facilitated the induction of cellular senescence by excess thymidine in cancerous HeLa cells and normal human diploid fibroblast TIG-7 cells, suggesting its role in preventing cellular senescence [3].

In conclusion, Lbr is important for nuclear organization and heterochromatin regulation. The gene-edited mouse model for Lbr has significantly contributed to understanding PHA. Lbr also plays a role in suppressing cellular senescence, which helps in further exploring the mechanisms related to cell growth and specific blood disorders.