Normal viability of Kai1/Cd82 deficient mice

Abstract

The KAI1/CD82 tetraspanin is a widely expressed cell surface molecule thought to organize diverse cellular signaling processes. KAI1/CD82 suppresses metastasis but not tumorigenicity, establishing it as one of a class of metastasis suppressor genes. In order to further assess its functions, we have characterized the phenotypic properties of Kai1/Cd82 deleted mice, including viability, fertility, lymphocyte composition, blood chemistry and tissue histopathology, and of their wild-type and heterozygote littermates. Interestingly, Kai1/Cd82(-/-) showed no obvious genotype associated defects in any of these processes and displayed no genotype associated histopathologic abnormalities after 12 or 18 months of life. Expression profiles of non-immortal, wild-type and Kai1/Cd82(-/-) mouse embryo fibroblast (MEFs) indicated distinct sex-specific and genotype-specific profiles. These data identify 191 and 1,271 differentially expressed transcripts (by twofold at P < 0.01) based on Kai1/CD82 genotype status in female and male MEFs, respectively. Differentially expressed genes in male MEFs were surprisingly enriched for cell division related processes, suggesting that Kai1/Cd82 may functionally affect these processes. This suggests that Kai/Cd82 has an unappreciated role in the early establishment of proliferation and division when challenged with a new environment that might play a role in adaptability to new metastatic sites.

Keywords: CD82; gene knockout; metastasis suppressor.

Figure 1.

(A) Knock-out recombination strategy. (B) Southern blotting of wild-type (+/+) and homozygous deleted (−/−) Kai1/Cd82 mice. (C) Kai1/Cd82 immunoblot in proteins isolated from wild-type (+/+) and homozygous deleted (−/−) Kai1/Cd82 mouse spleens. (D) Immunohistochemical detection of Kai1/Cd82 in kidney sections from wild-type (+/+), heterozygous (+/−), and knockout (−/−) mice.

Figure 2.

(A) Gene expression of passage 1 cultures of Day 12.5. WT and null mouse embryos identify genes systemically regulated by Kai1/Cd82. Global effect of gene expression demonstrated using unsupervised multidimensional scaling analysis. F KO, female knockout (−/−); F WT, female wild type; M KO, male knockout (−/−); M WT, male wild-type mice. (B,C) Tmem87a and DPCA2 gene expressions that are affected by Cd82/Kai1 genotype. F = female, M = male, +/+ = WT, −/− = KO. Left: Microarray. Right: TaqMan validation.

Figure 3.

Metastasis-related genes differentially expressed in MEFs derived from wild-type and knock-out Kai1/Cd82 mice. Red is up-regulated, Green is down-regulated. Top: reference is male Cd82^+/+. Bottom: reference is female Cd82^+/+.