These transgenic mice express beta-galactosidase under the direction of the mouse Hmgcr, 3-hydroxy-3-methylglutaryl-Coenzyme A reductase, gene promoter. 
Breeding experiments revealed that the 14 tandem copies of the transgene are inserted into the X Chromosome. Hemizygous males and homozygous females are viable and fertile.
Beta-galactosidase expression is widespread and localized in the nucleus by the nuclear localization signal in front of the lacZ gene driven by the Hmgcr housekeeping gene promoter. Male hemizygotes and female homozygotes express beta-galactosidase in all tissues, starting at the two-cell stage onwards until adulthood. Due to the insertion site on the X Chromosome the transgene undergoes sequential inactivation during post-implantation development in hemizygous females. Hemizygous females (at 10.5 d.p.c.) exhibit beta-galactosidase activity in approximately 50% of cells, indicating X inactivation.

During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background.

These H253 transgenic mice express an X-linked transgene containing nuclear-targeted beta-galactosidase and female hemizgyotes exhibit X inactivation mosaicism.

Typically mice are recovered in 12-16 weeks. Contact Customer Service to place an order or for more information.

<a target="_blank" href="https://www.jax.org/jax-mice-and-services/customer-support" rel="noreferrer">Contact Customer Service</a> for more information.

B6.Cg-Tg(Hmgcr-lacZ)H253Sest/J Frozen Embryo