| First Author | Christa L | Year | 2000 |
| Journal | Eur J Biochem | Volume | 267 |
| Issue | 6 | Pages | 1665-71 |
| PubMed ID | 10712597 | Mgi Jnum | J:61125 |
| Mgi Id | MGI:1354472 | Doi | 10.1046/j.1432-1327.2000.01159.x |
| Citation | Christa L, et al. (2000) High expression of the human hepatocarcinoma-intestine-pancreas/pancreatic-associated protein (HIP/PAP) gene in the mammary gland of lactating transgenic mice. Secretion into the milk and purification of the HIP/PAP lectin. Eur J Biochem 267(6):1665-71 |
| abstractText | The human hepatocarcinoma-intestine-pancreas/pancreatic-associated protein (HIP/PAP) gene was previously identified because of its increased expression in primary liver cancers and during the acute phase of pancreatitis. In normal tissues, HIP/PAP is expressed both in endocrine and exocrine cells of the intestine and pancreas. HIP/PAP is a lactose binding C-type lectin which acts as an adhesion molecule for rat hepatocytes. The aim of the work was to study the HIP/PAP secretory pathway and to produce high levels of HIP/PAP in the milk of lactating transgenic mice. In view of its lactose C-type lectin properties, we have studied the consequences of the expression of HIP/PAP on mammary epithelial cells. In homozygous mice, production reached 11.2 mg.mL-1 of milk. High levels of soluble and pure HIP/PAP (18.6 mg) were purified from 29 mL of milk. The purified protein was sequenced and the N-terminal amino acid of the mature HIP/PAP was identified as Glu27, thus localizing the site of cleavage of the signal peptide. The HIP/PAP transgene was only expressed in the mammary gland of lactating transgenic mice. HIP/PAP was detected by immunofluorescence in the whole gland, but labelling was heterogeneous between alveolar clusters, with strongly positive sparse cells. Using immuno electron microscopy, HIP/PAP was observed in all the compartments of the secretory pathway within the mammary epithelial cells. We provide evidence that HIP/PAP is secreted through the Golgi pathway. However, the number of distended Golgi saccules was increased when compared to that found in wild-type mouse mammary cells. These modifications could be related to HIP/PAP C-type lectin specific properties. |
