RESUMO
CD14 is a myelomonocytic differentiation antigen expressed by monocytes, macrophages, and activated granulocytes and is detectable with the monoclonal antibodies MO2, MY4, and LeuM3. Analyses of complementary DNA and genomic clones of CD14 show that it has a novel structure and that it maps to chromosome 5 within a region containing other genes encoding growth factors and receptors; it may therefore represent a new receptor important for myeloid differentiation. In addition, the CD14 gene is included in the "critical" region that is frequently deleted in certain myeloid leukemias.
Assuntos
Antígenos de Diferenciação/genética , Substâncias de Crescimento/genética , Monócitos/imunologia , Receptores de Superfície Celular/genética , Animais , Anticorpos Monoclonais , Antígenos de Diferenciação/imunologia , Diferenciação Celular , Mapeamento Cromossômico , Cromossomos Humanos Par 5 , DNA/genética , Eletroforese em Gel de Poliacrilamida , Granulócitos/imunologia , Humanos , Técnicas de Imunoadsorção , Leucemia/genética , Receptores de Lipopolissacarídeos , Macrófagos/imunologia , Camundongos , Síndromes Mielodisplásicas/genética , Hibridização de Ácido Nucleico , RNA Mensageiro/genéticaRESUMO
A panel of 22 monoclonal antibodies (MAbs) recognizing 21 distinct human cell surface antigens was tested by mixed hemadsorption assays for reactivity with a large number of rodent-human somatic cell hybrids containing different subsets of the human chromosome complement. The serological typing results permit the assignment of six gene loci determining cell surface antigens to human chromosomes 3, 6, 11, 19, 20, and 22. In addition, analysis of hybrids retaining deleted copies (but no normal homologs) of specific human chromosomes provides regional assignments for 18 gene loci, located on seven different chromosomes. These findings extend and refine the genetic map for human cell surface antigens and identify new selectable markers for defined chromosome segments.
Assuntos
Antígenos de Superfície/genética , Mapeamento Cromossômico , Marcadores Genéticos , Animais , Anticorpos Monoclonais , Cricetinae , Humanos , Células Híbridas , Camundongos , Células Tumorais CultivadasRESUMO
Thy-1 is a cell surface differentiation marker which shows distinct patterns of tissue-specific expression in different species. In man, the Thy-1 antigen is encoded by chromosome 11. We have examined the regulatory signals determining human Thy-1 expression through serologic analysis of rodent-human somatic cell hybrids retaining human chromosome 11 in which the fusion partners belong to distinct differentiation lineages. Cell surface expression of human Thy-1 was determined by mixed hemadsorption assays with two monoclonal antibodies (mAb), K117 and L127, shown to detect authentic human Thy-1 through analysis of COS-7 monkey kidney cells transfected with a cloned human Thy-1 gene. Three different patterns of human Thy-1 expression were observed when hybrid cells, constructed with different human and rodent cell types, were tested with mAb K117 and L127. Hybrids formed between Thy-1+ human neuroblastoma cells and Thy-1- mouse neuroblastoma cells, or hybrids between Thy-1+ human fibroblasts and the Thy-1- mouse kidney carcinoma, RAG, retain human Thy-1 expression. In contrast, hybrids formed between either Thy-1+ human neuroblastoma cells or Thy-1+ human fibroblasts and Thy-1- mouse L cells lose expression of human Thy-1 even though chromosome 11 is retained. Finally, hybrids formed between Thy-1- human peripheral lymphocytes or a Thy-1- lymphoblastoid B cell line and Thy-1- Chinese hamster fibroblasts begin to express human Thy-1. These studies suggest that both positive and negative trans-acting signals may play a role in the tissue-specific regulation of the human Thy-1 gene.
Assuntos
Antígenos de Superfície/biossíntese , Regulação da Expressão Gênica , Células Híbridas/imunologia , Animais , Anticorpos Monoclonais/imunologia , Antígenos de Neoplasias/biossíntese , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Antígenos de Superfície/genética , Antígenos de Superfície/imunologia , Chlorocebus aethiops , Cromossomos Humanos Par 11 , Cricetinae , Cricetulus , Humanos , Células L/imunologia , Camundongos , Neuroblastoma/patologia , Especificidade de Órgãos , Antígenos Thy-1RESUMO
Cerebellar degeneration-related antigen (designated CDR34) was previously cloned by antibody screening of a cDNA library and was shown to be one of the target molecules recognized by autoantibodies in patients with paraneoplastic cerebellar degeneration. This molecule is distinctive in that it contains a tandem hexapeptide repetitive structure, presumably the basis for its high immunogenicity. In this study, we cloned the human CDR34 gene and proved that the entire repetitive sequence is encoded by a single exon without introns. We also showed that the nucleotide repeats are preserved only in the protein-coding sequences, suggesting evolutionary constraint in this region of the gene. Corresponding mouse cDNA clones were also isolated, which encoded a larger molecule with very similar hexapeptide repeating units. Comparison of the human and mouse repeats revealed a highly conserved Glu-Asp core in each unit, implicating the functional significance of this motif. Chromosomal mapping by somatic cell hybrid analysis mapped CDR34 to both human and mouse chromosomes X, and in situ hybridization further assigned CDR34 to human Xq24-q27.