Video Experimental Relacionado
Updated: Aug 24, 2026

11:06
Identifying DNA Mutations in Purified Hematopoietic Stem/Progenitor Cells
Published on: February 24, 2014
Secuencia de ADN para un promotor de bajo nivel del gen lacrepresor y una mutación de promotor "arriba"
Nature
|August 24, 1978
Resumen
Los investigadores secuenciaron el promotor del gen represivo de la lactosa (lacI) y un promotor del gen represivo de la lactosa.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética La genética.
- Regulación genética Reglamento genético.
Sus antecedentes:
- El gen represor de lactosa (lacI) es un gen expresado constitutivamente.
- Comprender la regulación génica es crucial para varios procesos biológicos.
Objetivo del estudio:
- Para secuenciar la región promotora del gen lacI de expresión débil.
- Identificar la base genética de una mutación del promotor "superior" (Iq) que mejora la expresión lacI.
Principales métodos:
- Secuenciación del ADN del promotor lacI y el mutante Iq.
- Clonar el gen lacL en un pequeño plásmido para ayudar a la secuenciación.
Principales resultados:
- El promotor lacI y la mutación de IQ fueron secuenciados con éxito.
- Se identificó un solo cambio de base en la posición -35 como la causa del aumento de 10 veces en la expresión lacI en el mutante de IQ.
Conclusiones:
- Un cambio específico de base en la región promotora mejora significativamente la expresión génica.
- Este hallazgo proporciona información sobre los mecanismos de regulación del promotor genético.
Videos de Conceptos Relacionados
Operons
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...
Conservative Site-specific Recombination and Phase Variation
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
The Eukaryotic Promoter Region
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
The Eukaryotic Promoter Region
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
Operon 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...
Inducible 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...

