Molecular and cytological features of the mouse B-cell lymphoma line iMycEμ-1

The morphological features and the surface marker expression profile of the iMycEμ-1 cells were evaluated using cytological methods and FACS, respectively. The cytogenetic make-up of the iMycEμ-1 cells was assessed by spectral karyotyping (SKY). The expression of the inserted MycHis gene was determined using RT-PCR and qPCR. Clonotypic immunoglobulin gene arrangements were detected by Southern blotting. The global gene expression program of the iMycEμ-1 cells and the expression of 768 "pathway" genes were determined with the help of the Mouse Lymphochip？ and Superarray？ cDNA micro- and macroarrays, respectively. Array results were verified, in part, by RT-PCR and qPCR.Consistent with their derivation from LBL, the iMycEμ-1 cells were found to be neoplastic IgMhighIgDlow lymphoblasts that expressed typical B-cell surface markers including CD40, CD54 (ICAM-1), CD80 (B7-1) and CD86 (B7-2). The iMycEμ-1 cells harbored a reciprocal T(9;11) and three non-reciprocal chromosomal translocations, over-expressed MycHis at the expense of normal Myc, and exhibited gene expression changes on Mouse Lymphochip？ microarrays that were consistent with MycHis-driven B-cell neoplasia. Upon comparison to normal B cells using eight different Superarray？ cDNA macroarrays, the iMycEμ-1 cells showed the highest number of changes on the NFκB array.The iMycEμ-1 cells may provide a uniquely useful model system to study the growth and survival requirements of Myc-driven mouse LBL in vitro.Gene-targeted iMycEμ mice contain a single-copy mouse MycHis (c-myc) cDNA that has been inserted in opposite transcriptional orientation in the mouse immunoglobulin heavy-chain gene cluster, Igh. The specific insertion site of the MycHis transgene is in the intervening region of the Igh joining gene locus, JH, and the intronic heavy-chain enhancer, Eμ. The inserted transgene encodes a C-terminal His6 tag that is useful to distinguish message and protein encoded by MycHis and normal Myc [1]. The iMycEμ mice prov