Identification of Myc-regulated microRNAs in mouse B cell lymphomas. Mus musculus

We previously described the use of a spotted oligonucleotide array to identify the mir-17 cluster as a direct transcriptional target of Myc. In order to determine whether Myc regulates additional miRNAs, we produced custom microarrays with an expanded set of probes capable of assaying the expression of 313 human miRNAs and 233 mouse miRNAs. miRNA expression was assayed in a murine model of Myc-induced B cell lymphoma. In this system, bone marrow from p53-/- mice is infected with a retrovirus that produces a Myc-estrogen receptor fusion protein (MycER). Infected cells form polyclonal B cell lymphomas in the presence of 4-hydroxytamoxifen (4-OHT), which activates the MycER fusion protein. RNA from subcutaneous tumors with high Myc activity (animals treated continuously with 4-OHT) and low Myc activity (animals in which 4-OHT was withdrawn after tumor formation) was analyzed. Keywords: Dose Response Overall design: RNA from 2 subcutaneous MycER tumors with high Myc activity (animals treated continuously with 4-OHT) and 2 tumors with low Myc activity (animals in which 4-OHT was withdrawn after tumor formation) was analyzed.