title: Lamina-associated polypeptide 2 (LAP2) expression in fish and amphibians.
abstract: Somatic and germinal cells of 15 fish and 33 amphibian species were examined by SDS-PAGE followed by immunoblotting to determine the expression of LAP2 (lamina-associated polypeptide 2). LAP2 expression in frogs, salamanders and fish does not vary with the mode of reproduction. In fish and frog cells, a rim-like LAP2 positive region was detected around the nucleus by indirect immunofluorescence microscopy. The cell distribution and expression patterns of LAP2 in fish, frogs and salamanders are comparable with those found in Xenopus and zebrafish. The mammalian somatic cell pattern, which may also occur in gymnophione amphibians, includes LAP2alpha, beta and gamma as major isoforms, whereas LAP2alpha does not occur in cells of fish, frogs and salamanders. In fish, LAP2gamma is the major isoform of somatic cells, suggesting that LAP2gamma may be ancestral. However, in the rainbow trout, as in frogs and salamanders, LAP2beta was the major somatic isoform. Fish and frog sperm only express low molecular weight polypeptides. In contrast, fish and frog oocytes express an oocyte-specific LAP2 isoform of high molecular weight. In the toad Bufo marinus this isoform becomes upregulated in pre-vitellogenic oocytes of 150-200 microm in diameter. The absence of LAP2alpha and the differential expression of LAP2 isoforms in somatic and germ cells, as found in fish and frogs, may be ancestral vertebrate characters. In spite of differences in developmental time, the LAP2 isoforms of somatic cells are upregulated during gastrulation, suggesting that LAP2 may be implicated in the early development of fish and frog.
authors.affiliation: Departamento de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito. edelpino@puceuio.puce.edu.ec
authors.forename: Eugenia M
authors.initials: EM
authors.lastname: Del-Pino
authors.forename: Fabián E
authors.initials: FE
authors.lastname: Sáenz
authors.forename: Oscar D
authors.initials: OD
authors.lastname: Pérez
authors.forename: Federico D
authors.initials: FD
authors.lastname: Brown
authors.forename: María-Eugenia
authors.initials: ME
authors.lastname: Avila
authors.forename: Verónica A
authors.initials: VA
authors.lastname: Barragán
authors.forename: Nisrine
authors.initials: N
authors.lastname: Haddad
authors.forename: Micheline
authors.initials: M
authors.lastname: Paulin-Levasseur
authors.forename: Georg
authors.initials: G
authors.lastname: Krohne
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005399:Fishes; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D009865:Oocytes / Q000378:metabolism; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011898:Ranidae / Q000378:metabolism*; D051381:Rats; D013094:Spermatozoa / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D014018:Tissue Distribution; D015854:Up-Regulation; D014562:Caudata / Q000378:metabolism*; D015027:Zebrafish
chemical_list: D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D020033:Protein Isoforms; C093413:lamina-associated polypeptide 2