Video Experimental Relacionado
Updated: May 11, 2026
11:22
Measuring the Kinetics of mRNA Transcription in Single Living Cells
Published on: August 25, 2011
Resumen
La proteína del receptor de AMP cíclico (CRP) redirige la ARN polimerasa al promotor lac al eliminarlo activamente de un sitio de unión de ADN superpuesto. Esta interacción implica que la polimerasa abandone la plantilla de ADN para volver a unirse al promotor.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética La genética.
- La bioquímica es la bioquímica.
Sus antecedentes:
- El promotor lac es un elemento regulador clave en la expresión génica.
- La ARN polimerasa que se une al promotor inicia la transcripción.
- Se sabe que la proteína del receptor de AMP cíclico (CRP) regula el inicio de la transcripción.
Objetivo del estudio:
- Para dilucidar el mecanismo de entrada de la ARN polimerasa en el promotor lac.
- Investigar el papel del sitio de interacción P2 y CRP en este proceso.
Principales métodos:
- Ensayos de unión in vitro. ensayos de unión in vitro.
- Experimentos de competición de plantillas para estudiar el movimiento de la polimerasa.
- Investigando la interacción entre la ARN polimerasa, el promotor lac, y la CRP.
Principales resultados:
- La unión de la ARN polimerasa en el sitio P2 no conduce al deslizamiento hacia el promotor.
- La ARN polimerasa debe disociarse del ADN para volver a unirse al promotor.
- La CRP elimina activamente la polimerasa de P2 y facilita su unión al promotor.
Conclusiones:
- La unión de CRP al ADN elimina el promotor y lo modifica para una asociación eficiente de ARN polimerasa.
- La entrada de la ARN polimerasa en el promotor lac implica la disociación y la nueva unión, facilitada por la CRP.
Videos de Conceptos Relacionados
02:09Operons
Prokaryotes can control gene expression through operons—DNA sequences consisting of regulatory elements and clustered, functionally related protein-coding genes. Operons use a single promoter sequence to initiate transcription of a gene cluster (i.e., a group of structural genes) into a single mRNA molecule. The terminator sequence ends transcription. An operator sequence, located between the promoter and structural genes, prohibits the operon’s transcriptional activity if bound by a repressor...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
01:53Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
01:47Transcription Initiation
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...
The promoters and enhancers and their accessory proteins allow tight regulation of...
01:23Operon Model
The operon model represents a fundamental mechanism of gene regulation in prokaryotes, enabling coordinated expression of genes involved in related metabolic or functional pathways. Operons consist of structural genes, a promoter, and an operator, with transcription regulated by repressors, activators, and small effector molecules.Structure and Function of OperonsAn operon is a cluster of structural genes transcribed together under the control of a single promoter. The promoter region...
01:25Inducible Operons: lac Operon
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA (thiogalactoside...