Structure-function analysis of BCL2$\alpha$ and characterization of BMP-7 null mice
BCL2$\alpha$ is known to protect cells from apoptosis. To determine the functional domains of BCL2$\alpha$ critical for its role in apoptosis, I generated different deletion and point mutants of BCL2$\alpha$. These mutants under the regulation of CMV or RSV-LTR promoter were transfected into human preB cell line 697. The stable transfectants were tested for their ability to protect the cells from apoptosis induced by dexamethasone treatment. Although the transmembrane domain is required for membrane localization, BCL2$\alpha$ did not require it to protect the cells from apoptosis. Point mutations like T7D, G27A, and W30A did not affect function of BCL2$\alpha$. Point mutations like T7A, S24A, and S24D reduced the ability of BCL2$\alpha$ in protecting cells against apoptosis. Point mutations like G194A and D196A inactivated BCL2$\alpha$. While incorporation of point mutations like T7A, T7D, S24A, S24D, G27A, and E29K did not affect the ability of BCL2$\alpha$ to bind BAX, mutation like G194A prevented BCL2$\alpha$ to bind BAX. The mutation D196A reduced the ability of BCL2$\alpha$ to bind BAX. These studies imply that G194 and D196 of BCL2$\alpha$ are critical for its binding to BAX and for its ability to protect cells from apoptosis. While generating BCL2$\alpha$ transgenic mice, I found that in transgenic line TG114 the Bmp7 gene, a member of the TGF$\beta$ superfamily, was inactivated by insertional mutagenesis due to transgene integration. The Bmp7 homozygous null condition in mice was a postnatal lethal mutation and was associated with various developmental defects: holes in basisphenoid bone and xyphoid cartilage, retarded ossification or bones, fused ribs and vertebrae, underdeveloped neural arches of lumbar and sacral vertebrae, polydactyly of hind limbs, kinked tail, reduced number of nephrons, polycystic kidney, lack of retinal pigmentation, and retarded lens development. These findings indicate that BMP7 is an important signaling molecule for normal development of mammalian skeleton, kidney, and eye. ^
Biology, Anatomy|Biology, Molecular|Biology, Genetics|Health Sciences, Human Development
"Structure-function analysis of BCL2$\alpha$ and characterization of BMP-7 null mice"
(January 1, 1997).
ETD Collection for Thomas Jefferson University.