title: Expression of microsomal triglyceride transfer protein in lipoprotein-synthesizing tissues of the developing chicken embryo.
abstract: In contrast to mammals, in the chicken major sites of lipoprotein synthesis and secretion are not only the liver and intestine, but also the kidney and the embryonic yolk sac. Two key components in the assembly of triglyceride-rich lipoproteins are the microsomal triglyceride transfer protein (MTP) and apolipoprotein B (apoB). We have analyzed the expression of MTP in the embryonic liver, small intestine, and kidney, and have studied the expression of MTP in, and the secretion of apoB from, the developing yolk sac (YS). Transcript and protein levels of MTP increase during embryogenesis in YS, liver, kidney, and small intestine, and decrease in YS, embryonic liver, and kidney after hatching. In small intestine, the MTP mRNA level rises sharply during the last trimester of embryo development (after day 15), while MTP protein is detectable only after hatching (day 21). In the YS of 15- and 20-day old embryos, apoB secretion was detected by pulse-chase metabolic radiolabeling experiments and subsequent immunoprecipitation. Taken together, our data reveal the importance of coordinated production of MTP and apoB in chicken tissues capable of secreting triglyceride-rich lipoproteins even before hatching.
authors.affiliation: Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
authors.forename: Christine
authors.initials: C
authors.lastname: Eresheim
authors.affiliation: Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Plieschnig
authors.affiliation: Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
authors.forename: N Erwin
authors.initials: NE
authors.lastname: Ivessa
authors.affiliation: Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Schneider
authors.affiliation: Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria. Electronic address: marcela.hermann@meduniwien.ac.at.
authors.forename: Marcela
authors.initials: M
authors.lastname: Hermann
mesh_terms: D000818:Animals; D001055:Apolipoproteins B / Q000378:metabolism; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002642:Chick Embryo; D002645:Chickens / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009928:Organ Specificity
chemical_list: D001055:Apolipoproteins B; D030161:Avian Proteins; D002352:Carrier Proteins; C106092:microsomal triglyceride transfer protein
keywords: Apolipoprotein B; Development; Embryo; Lipoprotein; Microsomal triglyceride transfer protein; Yolk sac; chicken