Video Experimental Relacionado
Updated: Jun 18, 2026
08:19
Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster
Published on: December 19, 2011
La modulación de un factor de transcripción contrarresta el silenciamiento de genes heterocromáticos en Drosophila
1Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Cell
|April 6, 2001
Resumen
El silenciamiento de genes en Drosophila muestra variación debido a la heterocromatina.
Área de la Ciencia:
- Biología del desarrollo Biología del desarrollo.
- Genética La genética.
- La epigenética es la epigenética.
Sus antecedentes:
- La variación, un fenómeno común de silenciamiento de genes, implica una expresión génica estocástica encendido/apagado.
- Los mecanismos subyacentes de esta estocasticidad, particularmente dentro de la heterocromatina, siguen siendo poco conocidos.
Objetivo del estudio:
- Investigar las bases del silenciamiento y variación de genes estocásticos en Drosophila.
- Explorar el papel de la unión del factor de transcripción y la plasticidad de la heterocromatina en la regulación de la expresión génica.
Principales métodos:
- Utilizó un sistema condicional en Drosophila para sondear la función de la heterocromatina durante el desarrollo del ojo.
- Niveles manipulados del factor de transcripción GAL4 para evaluar su impacto en el silenciamiento del gen reportero (GFP).
- Monitoreo simultáneo de la expresión de un gen cercano para determinar el tamaño de las regiones activadas dentro de la heterocromatina.
Principales resultados:
- La frecuencia de silenciamiento de genes demostró una sensibilidad extrema a los niveles de GAL4, lo que sugiere que la ocupación del sitio de unión influye en el estado silenciado.
- Se descubrió que el estado silenciado era plástico, con desrepresión génica espontánea observada tanto en las células que se dividen como en las que se diferencian.
- El análisis reveló que el tamaño de las regiones activadas dentro de la heterocromatina es pequeño.
Conclusiones:
- Proponer que la variación surge de la capacidad de la heterocromatina para inhibir la exposición transitoria de los sitios de unión al factor de transcripción.
- La estructura y la dinámica de la heterocromatina juegan un papel crucial en la regulación de la expresión génica estocástica.
- La comprensión de estos mecanismos proporciona información sobre la regulación epigenética y los fenómenos de silenciamiento de genes.
Videos de Conceptos Relacionados
02:32Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
02:45The Ratio of X Chromosome to Autosomes
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
02:50Dosage Compensation
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...