Cell Type-specific Expression of LINE-1 Open Reading Frames 1 and 2 in Fetal and Adult Human Tissues
| Autor: | Kristin Dammann, Heidrun Lauke, Nerbil Kilic, Süleyman Ergün, Fariba Chalajour, Wolf H. Strätling, Frank Schnieders, Gerald G. Schumann, Christian Buschmann, Jochen Heukeshoven |
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| Rok vydání: | 2004 |
| Předmět: |
Adult
Male Somatic cell Angiogenesis Placenta viruses Molecular Sequence Data Gene Expression Retrotransposon Biology Peptide Mapping Biochemistry Genome Muscle Smooth Vascular Open Reading Frames Fetus Vasculogenesis Peptide mass fingerprinting Testis Humans Coding region Amino Acid Sequence Molecular Biology Aged Epididymis Sertoli Cells Leydig Cells Proteins Cell Biology Middle Aged Immunohistochemistry Spermatozoa Molecular biology Open reading frame Long Interspersed Nucleotide Elements Protein Biosynthesis Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization |
| Zdroj: | Journal of Biological Chemistry. 279:27753-27763 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m312985200 |
| Popis: | The LINE-1 (L1) family of non-long terminal repeat retrotransposons is a major force shaping mammalian genomes, and its members can alter the genome in many ways. Mutational analyses have shown that coexpression of functional proteins encoded by the two L1-specific open reading frames, ORF1 and ORF2, is an essential prerequisite for the propagation of L1 elements in the genome. However, all efforts to identify ORF2-encoded proteins have failed so far. Here, applying a novel antibody we report the presence of proteins encoded by ORF2 in a subset of cellular components of human male gonads. Immunohistochemical analyses revealed coexpression of ORF1 and ORF2 in prespermatogonia of fetal testis, in germ cells of adult testis, and in distinct somatic cell types, such as Leydig, Sertoli, and vascular endothelial cells. Coexpression of both proteins in male germ cells is necessary for the observed genomic expansion of the number of L1 elements. Peptide mass fingerprinting analysis of a approximately 130-kDa polypeptide isolated from cultured human dermal microvascular endothelial cells led to the identification of ORF2-encoded peptides. An isolated approximately 45-kDa polypeptide was shown to derive from nonfunctional copies of ORF2 coding regions. The presence of both ORF1- and ORF2-encoded proteins in vascular endothelial cells and its apparent association with certain stages of differentiation and maturation of blood vessels may have functional relevance for vasculogenesis and/or angiogenesis. |
| Databáze: | OpenAIRE |
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