Video Experimental Relacionado
Updated: Jun 19, 2026
06:40
G2-seq: A High Throughput Sequencing-based Technique for Identifying Late Replicating Regions of the Genome
Published on: March 22, 2018
El silenciamiento de la transcripción y la proteína de longevidad Sir2 es una histona desacetilasa dependiente de NAD
S Imai1, C M Armstrong, M Kaeberlein
1Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
Nature
|February 29, 2000
Resumen
La levadura Sir2, una histona desacetilasa, silencia los genes y extiende la vida útil mediante la eliminación de los grupos acetil de las histonas. Esta desacetilación dependiente de NAD vincula el metabolismo, el silenciamiento de genes y el envejecimiento.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética La genética.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La levadura Sir2 es un componente clave de la heterocromatina, que regula el silenciamiento de genes, la recombinación y la vida útil.
- Las lisinas específicas en las histonas H3 y H4 son cruciales para el silenciamiento, con patrones de acetilación correlacionados con la cromatina activa o silenciada.
- La sobreexpresión de Sir2 conduce a la desacetilación global de histonas, lo que sugiere su papel como una histona desacetilasa.
Objetivo del estudio:
- Para investigar la actividad enzimática de las proteínas Sir2 de levadura y ratón.
- Para determinar los objetivos específicos de la histona y el papel del nicotinamida adenina dinucleótido (NAD) en la actividad de la desacetilasa de Sir2.
- Para vincular la función de la desacetilasa de Sir2 a sus funciones in vivo en el silenciamiento, la supresión de la recombinación y la extensión de la vida útil.
Principales métodos:
- Análisis bioquímicos para medir la actividad de la histona desacetilasa.
- Análisis de las proteínas Sir2 de levadura y ratón.
- Análisis mutacional del gen SIR2.
- Estudios in vivo que evalúan el silenciamiento genético, la recombinación y la vida útil replicativa.
Principales resultados:
- Las proteínas Sir2 de levadura y ratón funcionan como desacetilasas de histonas dependientes de NAD.
- Sir2 desacetila específicamente las lisinas 9 y 14 de la histona H3 y la lisina 16 de la histona H4.
- Las mutaciones en SIR2 perjudican su actividad de la desacetilasa, lo que se correlaciona con defectos en el silenciamiento, la supresión de la recombinación y la extensión de la vida útil.
Conclusiones:
- La actividad NAD-dependiente de la histona desacetilasa de Sir2 es esencial para sus funciones biológicas en la levadura.
- Este mecanismo proporciona un vínculo molecular entre el metabolismo, el silenciamiento genómico y el envejecimiento.
- Los hallazgos pueden extenderse a los eucariotas superiores, lo que sugiere funciones conservadas para la desacetilación dependiente de NAD.
Videos de Conceptos Relacionados
01:53RNA Stability
Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...
01:53RNA Stability
Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...
02:30siRNA - Small Interfering RNAs
Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional level in some cases. siRNAs are important for protecting cells against viral infections and silencing transposable genetic elements.
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
02:15Replicative Cell Senescence
Replicative cell senescence is a property of cells that allows them to divide a finite number of times throughout the organism's lifespan while preventing excessive proliferation. Replicative senescence is associated with the gradual loss of the telomere — short, repetitive DNA sequences found at the end of the chromosomes. Telomeres are bound by a group of proteins to form a protective cap on the ends of chromosomes. Embryonic stem cells express telomerase — an enzyme that adds the telomeric...
02:15Replicative Cell Senescence
Replicative cell senescence is a property of cells that allows them to divide a finite number of times throughout the organism's lifespan while preventing excessive proliferation. Replicative senescence is associated with the gradual loss of the telomere — short, repetitive DNA sequences found at the end of the chromosomes. Telomeres are bound by a group of proteins to form a protective cap on the ends of chromosomes. Embryonic stem cells express telomerase — an enzyme that adds the telomeric...
01:29Translational Regulation
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...