STOCK Tg(Actb-GFP,-BBS4)B4T78Vcs/J

Stock number: 028027
Product name: BBS4^tg
Research areas: Cell Biology Research, Research Tools

Description

The Actb promoter drives expression of human BBS4, GFP and an S tag in this transgenic model of Bardet-Biedl syndrome (BBS).

Detailed description

Bbs4 (Bardet-Biedl syndrome 4 (human)) is a member of a family of genes involved with the formation and function of primary cilia. These cellular projections act as antennas that transduce extracellular signals into cells that regulate cell cycle, embryonic development, and tissue homeostasis. Defects in Bbs4 cause retinal degeneration and male infertility in mice. It is one of several genes associated with human Bardet-Biedl Syndrome (BBS), a ciliary dysfunction disorder with a range of physiological characteristics.

These mice carry a human BBS4 transgene flagged with GFP and an S-tag under the control of the beta actin (Actb) promoter. As compared to endogenous BBS4 expression, lower expression of the transgene is found in the eye, and higher expression is detected in the testis. Overall expression of the transgene is highest in testis, followed by brain, adipose, eye, heart and very slight expression is seen in trachea, lungs and bone. No expression is observed in the liver or skin. Immunofluorescence assays confirm that localization of transgene expression is similar to endogenous BBS4, such that it localizes to the centrosome and cilia. Transgenic animals have no overt phenotype.

Despite tissue-specific variable expression of the transgene, human BBS4 is able to complement the deficiencies of Bbs4 and rescue all BBS phenotypes when crossed onto the Bbs4 null genetic background (see Stock No. 010728 and Stock No. 010752). Transgene expression rescues male infertility, obesity, leptin resistance, retinopathy, hydrocephalus, and ciliopathy characteristic of null animals.

The GFP and S-tag enable localization studies and tandem affinity purification. GFP signal is too weak to be detected without enhancement. Immunofluorescence or western blotting is required to confirm the presence of GFP.

Development

Human BBS4 and a localization and purification (LAP) tag (GFP followed by a cleavage site for Tobacco Etch Virus (TEV) protease and an S-tag) were placed under the control of the beta actin (Actb) promoter in a transgenic vector. The vector was introduced to B6SJL (C57BL/6J x SJL/J) embryos. This strain was maintained on a mixed background incorporating C57BL/6, SJL and 129/SvJ by the donating laboratory.

Allele

Symbol: Tg(Actb-GFP,-BBS4)B4T78Vcs
Name: transgene insertion B4T78, Val C Sheffield
MGI accession ID: MGI:5697974
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: BBS4^tg
Marker symbol: Tg(Actb-GFP,-BBS4)B4T78Vcs
Marker name: transgene insertion B4T78, Val C Sheffield
Chromosome: UN
Strain of origin: C57BL/6J x SJL/J
Expressed genes: GFP,Green Fluorescent Protein,; BBS4,Bardet-Biedl syndrome 4,human
Site of expression: GFP is expressed in various tissues including brain, eye, testis, heart, kidney, and adipose tissue.
Molecular note: Human BBS4 and a localization and purification (LAP) tag (GFP followed by a cleavage site for Tobacco Etch Virus (TEV) protease and an S-tag) were placed under the control of the beta actin (Actb) promoter in a transgenic vector. Expression of the transgene is highest in testis, followed by brain, adipose, eye, heart and very slight expression is seen in trachea, lungs and bone. No expression is observed in the liver or skin. Immunofluorescence assays confirm that localization of transgene expression is similar to endogenous BBS4, such that it localizes to the centrosome and cilia.