Gene expression profile in B cells from Xid and Btk KO mice. Mus musculus

Bruton's tyrosine kinase (Btk) is important for B lymphocyte development. To identify genes that are differentially expressed in primary B cells lacking functional Btk, splenocytes from X-linked immunodeficiency (Xid), Btk knockout (KO) and immunocompetent CBA mice, were used in microarrays containing more than 12,000 genes and expressed sequence tags (ESTs). We found 4515 transcripts expressed in duplicate experiments in all three strains. Out of these, 38 were differentially expressed genes (21 up-regulated >2 fold and 17 down-regulated 2 fold) between the two strains. Moreover, when the 38 genes, which differed between immunocompetent CBA and Btk defective mice were ranked according to fold-increase, the levels in Btk KO mice were significantly more altered. This suggests that the defect in Btk KO mice is more severe and demonstrates that the mutant Btk protein in Xid mice does not generally function as dominant negative form. Keywords: Btk, DNA microarray, Xid, Btk KO, Real-Time PCR Overall design: 6 Affymetrix U74Av2 GeneChip arrays was run. Three initially with CBA, Xid and Btk KO mice and then additional three chips with new RNA preperations from new CBA, Xid and Btk KO mice.