RESUMEN
We have applied cDNA hybridization selection to nine YACs spanning 3 Mb of genomic DNA from a region centromeric to HLA-A to the histone cluster that lies telomeric to the human major histocompatibility complex (MHC). In addition to Class I genes and pseudogenes, we describe over 63 genes and 23 additional expressed sequence tags distributed throughout the region. Many of the full-length genes belong to gene families. Prominent among these are a group of genes encoding proteins showing homology to the carboxyl-terminal sequences of butyrophilin and an additional group of zinc finger genes. We also detected several previously undefined genes that are specifically expressed in cells of the immune system, indicating a more complex role of the MHC in the immune response than has been appreciated.
Asunto(s)
Mapeo Cromosómico/métodos , ADN Complementario/genética , Genes MHC Clase I/genética , Transcripción Genética , Secuencia de Aminoácidos , Secuencia de Bases , Cromosomas Artificiales de Levadura/genética , Evolución Molecular , Expresión Génica , Humanos , Datos de Secuencia Molecular , Familia de Multigenes/genética , Seudogenes/genética , ARN Mensajero/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Dedos de ZincRESUMEN
The human major histocompatability complex contains genes of both immune and nonimmune importance. Recently, several genes encoding novel, non-HLA products have been described in this area. We have performed positional cloning of short fragment cDNA sequences from the class I region of the human MHC using a hybridization selection approach. This report describes isolation of full-length cDNA clones and partial genomic clones that encode a protein that contains two domains rich in cysteine and histidine similar to those characteristic of metal-dependent DNA binding proteins (C3HC4). The predicted protein also contains a domain thought to form a coiled-coil that may promote dimerization. A third feature is a polyglutamic acid region near the carboxyl terminus of the conceptual protein. Because of these properties, we have named this gene product acid finger protein (AFP). Although the biological role of AFP is unknown at present, one potential function is binding of nucleic acids. The gene (ZNF173) is expressed in multiple tissues and is conserved among mammals. In particular, the mouse and human coding regions are highly conserved. In addition to AFP, other related sequences have been localized to the MHC, suggesting that multiple AFP-like genes exist in this area.
Asunto(s)
Proteínas de Unión al ADN/genética , Genes MHC Clase I , Hominidae/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Secuencia de Consenso , Secuencia Conservada , ADN Complementario , Proteínas de Unión al ADN/biosíntesis , Biblioteca de Genes , Humanos , Riñón/metabolismo , Complejo Mayor de Histocompatibilidad , Ratones , Datos de Secuencia Molecular , Mapeo Restrictivo , Homología de Secuencia de Aminoácido , Dedos de Zinc , alfa-FetoproteínasRESUMEN
It has previously been shown that cDNA hybridization selection can identify and recover novel genes from large cloned genomic DNA such as cosmids or YACs. In an effort to identify candidate genes for hemochromatosis, this technique was applied to a 320-kb YAC containing the HLA-A gene. A short fragment cDNA library derived from human duodenum was selected with the YAC DNA. Ten novel gene fragments were isolated, characterized, and localized on the physical map of the YAC.