THE MOUSE WNT-B-10 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 isolat ed cDNAs encoding Wnt-10B, a new member of the Wnt family of developme ntal control genes. This protein appears to be the mammalian orthologu e of Wnt-10B, first identified in several non-mammalian vertebrates an d recently in mouse. The mRNA expression pattern of mouse Wnt-10B indi cates that it is induced following activation of helper T cells, but i s also expressed in a variety of other tissues and cells of fetal or a dult origin. 93 bp at the 5' end of the cDNA clone are identical to se quences previously reported as 3' flanking genomic DNA adjacent to a m ouse mammary tumor virus (MMTV) provirus in the MMTV-induced BR6 mamma ry 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-1OB, pos sibly contributing to the oncogenic process. Consistent with this idea is the detection of hybrid MMTV-Wnt-10B transcripts in BR6 tumor cell s. T cells which produce abundant Wnt-10B mRNA were also found to prod uce protein.