The mouse Wnt-10B gene isolated from helper T cells is widely expressed and a possible oncogene in BR6 mouse mammary tumorigenesis.

From libraries made from activated mouse T lymphocytes, we have isolated cDNAs encoding Wnt-10B, a new member of the Wnt family of developmental control genes. This protein appears to be the mammalian orthologue of Wnt-10B, first identified in several non-mammalian vertebrates and recently in mouse. The mRNA expression pattern of mouse Wnt-10B indicates that it is induced following activation of helper T cells, but is also expressed in a variety of other tissues and cells of fetal or adult origin. 93 bp at the 5' end of the cDNA clone are identical to sequences previously reported as 3' flanking genomic DNA adjacent to a mouse mammary tumor virus (MMTV) provirus in the MMTV-induced BR6 mammary tumor, W26. Sequence analysis of tumor-derived genomic DNA confirms that the entire Wnt-10B gene is immediately adjacent to the provirus, suggesting that MMTV integration drives transcription of Wnt-10B, possibly contributing to the oncogenic process. Consistent with this idea is the detection of hybrid MMTV-Wnt-10B transcripts in BR6 tumor cells. T cells which produce abundant Wnt-10B mRNA were also found to produce protein.