RESUMEN
FK506-binding proteins (FKBPs) are cellular receptors for immunosuppressants that belong to a subgroup of proteins, known as immunophilins, with peptidylprolyl cis-trans isomerase (PPIase) activity. Sequence comparison suggested that the HD2-type histone deacetylases and the FKBP-type PPIases may have evolved from a common ancestor enzyme. Here we show that FKBP25 physically associates with the histone deacetylases HDAC1 and HDAC2 and with the HDAC-binding transcriptional regulator YY1. An FKBP25 immunoprecipitated complex contains deacetylase activity, and this activity is associated with the N-terminus of FKBP25, distinct from the FK506/rapamycin-binding domain. Furthermore, FKBP25 can alter the DNA-binding activity of YY1. Together, our data firmly establish a relationship between histone deacetylases and the FKBP enzymes and provide a novel and critical function for the FKBPs.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Histona Desacetilasas/metabolismo , Proteínas Represoras , Proteínas de Unión a Tacrolimus/metabolismo , Factores de Transcripción/metabolismo , Secuencia de Bases , Sitios de Unión , Clonación Molecular , Secuencia de Consenso , Proteínas de Unión al ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Escherichia coli , Genes Reporteros , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo , Células HeLa , Histona Desacetilasa 1 , Histona Desacetilasa 2 , Humanos , Células Jurkat , Cinética , Luciferasas/genética , Proteínas Nucleares/metabolismo , Oligodesoxirribonucleótidos/química , Oligodesoxirribonucleótidos/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Factores de Transcripción/genética , Transcripción Genética , Transfección , Factor de Transcripción YY1RESUMEN
YY1 is a sequence-specific DNA-binding transcription factor that has many important biological roles. It activates or represses many genes during cell growth and differentiation and is also required for the normal development of mammalian embryos. Previous studies have established that YY1 interacts with histone acetyltransferases p300 and CREB-binding protein (CBP) and histone deacetylase 1 (HDAC1), HDAC2, and HDAC3. Here, we present evidence that the activity of YY1 is regulated through acetylation by p300 and PCAF and through deacetylation by HDACs. YY1 was acetylated in two regions: both p300 and PCAF acetylated the central glycine-lysine-rich domain of residues 170 to 200, and PCAF also acetylated YY1 at the C-terminal DNA-binding zinc finger domain. Acetylation of the central region was required for the full transcriptional repressor activity of YY1 and targeted YY1 for active deacetylation by HDACs. However, the C-terminal region of YY1 could not be deacetylated. Rather, the acetylated C-terminal region interacted with HDACs, which resulted in stable HDAC activity associated with the YY1 protein. Finally, acetylation of the C-terminal zinc finger domain decreased the DNA-binding activity of YY1. Our findings suggest that in the natural context, YY1 activity is regulated through intricate mechanisms involving negative feedback loops, histone deacetylation, and recognition of the cognate DNA sequence affected by acetylation and deacetylation of the YY1 protein.
Asunto(s)
Acetilación , Proteínas de Unión al ADN/metabolismo , Proteínas Represoras/metabolismo , Proteínas de Saccharomyces cerevisiae , Factores de Transcripción/metabolismo , Acetiltransferasas/genética , Acetiltransferasas/metabolismo , Secuencia de Aminoácidos , Arginina/genética , Arginina/metabolismo , Sitios de Unión , ADN/metabolismo , Proteínas de Unión al ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Células HeLa , Histona Acetiltransferasas , Histona Desacetilasa 1 , Histona Desacetilasa 2 , Histona Desacetilasas/metabolismo , Humanos , Lisina/genética , Lisina/metabolismo , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Represoras/genética , Transactivadores/genética , Transactivadores/metabolismo , Factores de Transcripción/genética , Factor de Transcripción YY1 , Dedos de ZincRESUMEN
Yin Yang 1 (YY1) is a protein that activates and represses transcription of a large number of cellular and viral genes. In addition, studies suggest that YY1 may play an important role in development and differentiation. Here, we report the isolation and analysis of a YY1 genomic clone from a lambda human liver library. Fluorescence in situ hybridization with the YY1 clone has localized the YY1 gene to chromosome 14 band q32. A major YY1 gene transcription initiation site has been mapped to 478 bp upstream of the ATG translation start site. The proximal promoter contains multiple Sp1 transcription factor binding sites but lacks a consensus TATA or CCAAT box. Transient transfections and detailed deletion analyses localized the promoter to no more than 277 bp upstream from the major transcription start site. Finally, we have found that overexpression of the adenovirus E1A protein represses expression of a reporter gene directed by the YY1 promoter.
Asunto(s)
Proteínas de Unión al ADN/genética , Factores de Transcripción/genética , Proteínas E1A de Adenovirus/genética , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Humanos Par 14/genética , Clonación Molecular , ADN/genética , Cartilla de ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Expresión Génica , Genes Reporteros , Humanos , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , Transfección , Factor de Transcripción YY1RESUMEN
The hepatitis B virus X protein induces transcriptional activation of a wide variety of viral and cellular genes. In addition to its ability to interact directly with many nuclear transcription factors, several reports indicate that the X protein stimulates different cytoplasmic kinase signal cascades. Using the yeast two-hybrid screen, we have isolated a clone designated X-associated protein 3 (XAP3) that encodes a human homolog of the rat protein kinase C-binding protein. One of the activation domains of X (amino acids 90-122) is required for binding to XAP3, while the NH2-terminal part of XAP3 is necessary for binding to X. Both X and XAP3 bound specifically to the eta PKC isoenzyme synthesized in rabbit reticulocyte lysates. Overexpression of XAP3 enhanced X transactivation activity. These results support earlier findings that one of the mechanisms of transactivation by X is through involvement with the cellular protein kinase C pathway.
Asunto(s)
Proteínas Portadoras/metabolismo , Proteína Quinasa C/metabolismo , Transactivadores/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Northern Blotting , ADN Complementario/química , Humanos , Isoenzimas/metabolismo , Datos de Secuencia Molecular , Fosforilación , Conejos , Ratas , Activación Transcripcional , Proteínas Reguladoras y Accesorias ViralesRESUMEN
The results showed that microscopic structure in biennial roots, the contents of B and Mn in nutritive organ and beta-sitosterol content in roots, stems of Morinda officinalis were affected markedly. The total sugar content in the roots and aerial stems was decreased by 5.42%-15.29%.