Expression of the von Hippel-Lindau-binding protein-1 (Vbp1) in fetal and adult mouse tissues.

The von Hippel-Lindau (VHL) tumour suppressorgene product is believed to be involved in the down-regulation of transcriptional elongation by preventing the association of elongin B and C with the catalytic subunit elongin A. Alterations in the human VHL gene lead to VHL disease which is associated with various rare neoplasias, including haemangioblastoma of the central nervous system, retinal angioma, clear cell renal carcinoma and pheochromocytoma. Recently, a protein (VBP1) was isolated that was found to bind to the VHL protein in vivo. We have used the murine Vbp1 homologous cDNA to investigate the expression of the Vbp1 mRNA in the mouse by in situ hybridization and northern blot analysis. In fetal stages between days 9 and 18 of gestation, Vbp1 was expressed mainly in the central nervous system, retina and liver. In addition, at day 12, high expression was observed in the labyrinthine region of the placenta. In later stage placentas, Vbp1 expression was, however, considerably reduced. Northern blot analysis of adult mouse tissues showed that Vbp1 was ubiquitously expressed. In situ analysis on several adult tissues showed that in most tissues, transcripts were evenly distributed. In brain, eye, kidney and intestine, however, Vbp1 was expressed in specific cell types. Moreover, expression of the human VBP1 gene was investigated in cerebellum and in various tumours of VHL patients encompassinghaemangioblastomas, renal cell carcinomas and pheochromocytomas. In all of these tissues, VBP1 was ubiquitously expressed at low levels. However, no consistent differences in VBP1 expression levels could be detected between tumours and normal tissue. Mapping of the murine Vbp1 gene revealed conserved chromosomal localization between mouse and human in a region homologous to human Xq28.