Disease relevance of Xbp1

• Hepatocarcinogenesis-related transcription factor (HTF) was originally isolated from rats in which the expression was enhanced in hepatocellular carcinomas [1].
• To address the question of the role of CpG-rich sequences in gene expression, we investigated the effect of an HTF island on the activity of the polyomavirus middle T (pmt) oncogene. pmt is less transformant and less tumorigenic when it is introduced into cultured cells or newborn rats in the presence of an HTF island [2].

High impact information on Xbp1

• Transformed cells carrying pmt in the vicinity of the HTF island have a propensity to revert at a relatively high rate of about 2 X 10(-3) per cell per generation by a mechanism probably involving methylation of some CpG sites in the island [2].
• In vitro culture of young one-cell embryos using common embryo media (KSOM, BMOC, or HTF) for 18-22 h followed by culture in mR1ECM medium allows the successful in vitro development of blastocysts from one-cell embryos after 5 days from both outbred (SD) and inbred strains of rat (WF, LEW, F344, and PVG) [3].
• We investigated htf gene expression in rat tissues by Northern analysis and found that HTF expression was ubiquitous but was enriched in the liver [4].
• Consequently, HTF is thought to participate in hepatocyte growth as well as in hepatocarcinogenesis [4].
• Two hepatotrophic protein factors (HTF) were partially purified from the serum-free conditioned medium of the embryo rat fibroblastic cell line FRL [5].

Biological context of Xbp1

• HTF induced cell adherence to the culture plate, promoted life maintenance, scattering and enhanced 3H-Thymidine uptake into DNA and cell proliferation in two sensitive murine non-transformed, epithelial hepatocytic cell lines (C6 and C2.8) [5].

Analytical, diagnostic and therapeutic context of Xbp1

• Electrophoretic mobility shift assay demonstrated the DNA-binding ability of the recombinant HTF [6].

References