title: Molecular characterization and temporal expression profiling of presenilins in the developing porcine brain.
abstract: BACKGROUND
  The transmembrane presenilin (PSEN) proteins, PSEN1 and PSEN2, have been proposed to be the catalytic components of the gamma-secretase protein complex, which is an intramembranous multimeric protease involved in development, cell regulatory processes, and neurodegeneration in Alzheimer's disease. Here we describe the sequencing, chromosomal mapping, and polymorphism analysis of PSEN1 and PSEN2 in the domestic pig (Sus scrofa domesticus).
  
  
  RESULTS
  The porcine presenilin proteins showed a high degree of homology over their entire sequences to the PSENs from mouse, bovine, and human. PSEN1 and PSEN2 transcription was examined during prenatal development of the brain stem, hippocampus, cortex, basal ganglia, and cerebellum at embryonic days 60, 80, 100, and 114, which revealed distinct temporal- and tissue-specific expression profiles. Furthermore, immunohistochemical analysis of PSEN1 and PSEN2 showed similar localization of the proteins predominantly in neuronal cells in all examined brain areas.
  
  
  CONCLUSIONS
  The data provide evidence for structural and functional conservation of PSENs in mammalian lineages, and may suggest that the high sequence similarity and colocalization of PSEN1 and PSEN2 in brain tissue reflect a certain degree of functional redundancy. The data show that pigs may provide a new animal model for detailed analysis of the developmental functions of the PSENs.
authors.affiliation: Section for Molecular Genetics and Systems Biology, Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Tjele, Denmark. loneb.madsen@agrsci.dk
authors.forename: Lone B
authors.initials: LB
authors.lastname: Madsen
authors.forename: Bo
authors.initials: B
authors.lastname: Thomsen
authors.forename: Knud
authors.initials: K
authors.lastname: Larsen
authors.forename: Christian
authors.initials: C
authors.lastname: Bendixen
authors.forename: Ida E
authors.initials: IE
authors.lastname: Holm
authors.forename: Merete
authors.initials: M
authors.lastname: Fredholm
authors.forename: Arne L
authors.initials: AL
authors.lastname: Jørgensen
authors.forename: Anders L
authors.initials: AL
authors.lastname: Nielsen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000196:embryology* / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D053764:Presenilin-1 / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D053766:Presenilin-2 / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D034421:Sus scrofa; D013552:Swine; D013997:Time Factors
chemical_list: D008565:Membrane Proteins; D053764:Presenilin-1; D053766:Presenilin-2