MMH-GHs maintain a highly-differentiated phenotype at morphological and molecular levels. Panel A shows the immunofluorescence analysis of E-Cadherin, ZO-1 and cytokeratins expression and localization in MMH-GH clones, in a well polarized MMHline (MMHE14) and in a transformed, undifferentiated MMH line(MMH/Myc). Phase-contrast images and microphotographs of E-Cadherin immunostaining represent the same fields. Panel B shows the RT-PCR analysis of RNA extracted from an MMH clone, from adult liver as control and from two different MMH-GH cell lines (MMH-GH5 and MMH-GH9). The amplified fragments are shown in the left side of the panel, while in the right side the Southern Blot analysis of the same amplified sequences performed with oligonucleotides used as internal probes is shown. Normalization of RT-PCR was obtained by amplification of beta-actin cDNA. The genes considered are: liver-enriched transcription factors (HNF1a, HNF1b, HNF4), drug and carcinogen-activating and -detoxifying enzymes (Glutamine Synthethase, GLNS; UDP-glucuronosyl-transferase, UDP-GT; Cytochrome P450 1A1, Cyp1A1; Epoxide hydrolase, Eph) and gluconeogenesis supporting enzymes (Lactate dehydrogenase, LDH; Glutamate-oxaloacetate-transaminase 1, Got1; Glutamate-oxaloacetate-transaminase 2, Got2). Oligonucleotides used as forward and reverse primers for PCR and as internal probes in Southern Blot analysis are listed in Additional file: 2, together with the NCBI accession numbers of the sequences from which they were derived.