Disease relevance of Krt1-19

• Hepatocellular nodules and hepatocellular carcinoma were invariably negative for cytokeratin 19 [1].
• Phenotypically, the glandular epithelial cells of the furan-induced intestinal-type adenocarcinomas were immunohistochemically positive for cytokeratin 19, but exhibited a heterogeneous pattern of immunohistochemical staining for gamma-glutamyl transpeptidase and showed no detectable immunostaining for transforming growth factor alpha [2].
• Oval cells, cholangiofibroses, cystic cholangiomas and cholangiofibromas expressed cytokeratin 19, whereas parenchymal cells, foci of altered hepatocytes and hepatocellular adenomas did not; this observation does not support a precursor-product relationship between oval and parenchymal cells [3].

High impact information on Krt1-19

• The hematopoietic stem cell marker CD34 and hepatic oval cell markers such as albumin, alpha-fetoprotein (AFP), and cytokeratin 19 are all negative [4].
• At day 20 some cells in the colonies were positive for AFP, CK7, CK19, and GST-P [5].
• The cells produced albumin and displayed a cytokeratin (CK) pattern typical of hepatocytes (CK 8 and CK 18-positive and CK 19-negative) [6].
• CK19 was expressed, as in the control liver, in the epithelial cells of proliferated bile ductules in enlarged portal tracts but not in rosette-like structures of CBDL livers [7].
• In all animals of each experimental group, hyperplastic bile duct cells in areas of cholangiofibrosis and oval cells were positive for cytokeratin 19, an intermediate filament protein present only in bile duct cells in normal liver [1].

Biological context of Krt1-19

• The present results indicate that K18 and K19 gene expression is regulated at the transcriptional level [8].
• As testicular differentiation progressed, K19 mRNA disappeared and, from 14.5 days of gestation on, fetal Sertoli cells expressed exclusively K18 mRNA [8].
• The results reported here show first, that CKs are expressed before sexual differentiation in gonadal blastema in which no epithelial organization is observed, and second, that there is a CK 18/CK 19 shift in expression during morphogenesis of the testis which is not observed in the differentiating ovary [9].
• The percent aneuploid cells and CK 19 staining were tested statistically and were shown to be negatively correlated [10].
• In particular, cytokeratin 19 expression has been associated with the type II cell phenotype [11].

Anatomical context of Krt1-19

• We used degenerate primers for the amino- and carboxyl-terminal ends of the rod domains of intermediate filament proteins in reverse transcriptase-PCR experiments to identify and clone cytokeratins 8 and 19 (K8 and K19) from cardiac muscle of the adult rat [12].
• Northern blots showed that K8 has a 2.2-kb transcript and K19 has a 1.9-kb transcript in both adult cardiac and skeletal muscles [12].
• The changes in the transcriptional activity of K19 and K18 genes, observed in male gonads, occur characteristically at the very beginning of testicular differentiation [8].
• Cytokeratin 19 was also strongly expressed in all of the biliary epithelial cells, but in just some of the ductular hepatocytic cells, whereas only the latter cells were immunohistochemically positive for albumin and contained peroxisomes in their cytoplasm [13].
• RT-PCR analysis for the stem cell marker Thy1 and the hepatocytic markers CK-18, albumin, CK-19, and AFP was performed in the different cell populations [14].

Associations of Krt1-19 with chemical compounds

• Moreover, BrdU labeling kinetics indicated that the growth of neonatal islets occurred in the peripheral mantle region characterized by intense CK20 and CK19 immunoreactivity and not in the region composed of differentiated endocrine cells [15].
• The hepatocyte-like cells from the subcutaneous implantation site expressed mixed phenotypes of both hepatocyte and ductal cell, including the expression of alpha-fetoprotein, tyrosine amino-transferase, gamma-glutamyl transpeptidase, carbonic anhydrase II, and cytokeratin 19 [16].
• CK19 expression and branching morphogenesis were inhibited by dexamethasone, a mitogen-activated protein kinase kinase 1 (MEK1) inhibitor (PD98059), and a phosphatidyl inositol 3-kinase inhibitor (LY294002) [17].
• Sodium butyrate induced cytokeratin 19 expression and gamma-glutamyltranspeptidase activity, together with a large increase in gamma-glutamyltranspeptidase mRNA IV, a transcript expressed at high levels in biliary cells [18].
• Liver sections were obtained for in situ hybridization for procollagen alpha1(I) mRNA, immunohistochemical staining for SMA and cytokeratin 19, and histochemical staining for reticulin [19].

Other interactions of Krt1-19

• Switch in the expression of the K19/K18 keratin genes as a very early evidence of testicular differentiation in the rat [8].
• Dystrophin and K19 could be co-immunoprecipitated and co-purified from extracts of cardiac muscle, suggesting a link between the cytokeratins and the dystrophin-based cytoskeleton at the sarcolemma [12].
• Unique immunohistochemically detectable changes in CK expression were the loss of CK 13 expression in invasive TCC cells and the loss of CK 19 expression in induced TCC [10].
• In contrast, the amounts of mRNA encoding Wnt-7b, E-cadherin, and cytokeratin-19 increased during development and into adulthood [20].
• It was found that alpha-fetoprotein, albumin, and cytokeratin 19 are present in all cultured cells [21].

Analytical, diagnostic and therapeutic context of Krt1-19

• PCR products were cloned, sequenced and used as species-specific K18 and K19 riboprobes for in situ hybridization [8].
• Examination of cells lining the ducts by immunohistochemistry showed that these cells lost the ability to express albumin and stained more intensely for cytokeratin 19 and laminin [22].
• Immunofluorescence microscopy of cytokeratin 19 (CK19) was performed to assess the proliferation of bile ductules [7].
• In normal liver, 1 to 2 weeks after transplantation, mainly cells with a single phenotype, hepatocytic (expressing AFP and albumin) or bile ductular (expressing only CK-19), had proliferated [23].
• We evaluated ultrastructural features by transmission and scanning electron microscopy. gamma-glutamyl-transpeptidase (gamma GT) was visualized in cultured cells by enzyme histochemistry, and cytokeratin (CK)-7, CK-19, vimentin, and desmin staining was done by immunohistochemistry [24].

References