X Inactivation Center
X Inactivation Center - Related Videos
01:58
X-inactivation
0 Views •
2021
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results. Instead, in order to avoid this potential issue, female mammalian cells inactivate nearly all the genes in one of their X chromosomes during early embryonic development. In the nuclear envelope surrounding the cell nucleus, the inactivated X chromosome...
01:58
X-Inactivation
0 Views •
2019
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results. Instead, in order to avoid this potential issue, female mammalian cells inactivate nearly all the genes in one of their X chromosomes during early embryonic development. In the nuclear envelope surrounding the cell nucleus, the inactivated X chromosome...
01:22
Activation and Inactivation of G Proteins
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2023
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
03:19
Inactivation of Bacteria Using Light-Activated Flavin Mononucleotide
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2025
Source: Cheng, C., et al. Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate. J. Vis. Exp. (2022)This video demonstrates a method for evaluating the phototoxic effects of flavin mononucleotide (FMN) on pathogenic bacteria. Bacterial cultures are exposed to increasing concentrations of FMN and illuminated with visible light to generate reactive oxygen species (ROS) that damage cellular components. The surviving bacteria are then quantified to assess the...
02:40
Inactivation of Bacteriophages Using Exogenous Lipopolysaccharide to Generate Phage-Free Salmonella Cultures
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2026
Source: Fernández-Fernández, R., et. al. Bacteriophage Removal from Infected Salmonella Cultures. J. Vis. Exp. (2024)This video demonstrates the use of exogenous LPS (Lipopolysaccharide) as a receptor mimic to inactivate lytic bacteriophages in Salmonella cultures. Through sequential incubation, centrifugation, and washing, phages are eliminated, resulting in a viable, phage-free bacterial suspension for downstream applications.
FAQs
Within the Xic, regulatory control of Xist and Tsix helps determine whether Xist is expressed from a particular X chromosome. Xist then provides a chromosome-wide signal by coating that chromosome, while recruited chromatin-modifying factors establish compaction. This coordinated regulation links an initial choice at the locus to reduced transcription across the selected chromosome.
Chromatin-modifying factors convert the Xist coating signal into a compact chromosomal state. Their recruitment changes the organization of the selected X chromosome so that it becomes transcriptionally inactive, rather than leaving Xist as an isolated RNA signal. This step matters because dosage compensation depends on coordinated repression across the chromosome, not merely on regulating one gene.
Regulation at the Xic helps determine which X chromosome is selected for inactivation during early development. In XX cells, one of the two X chromosomes is chosen, whereas XY cells have only one X chromosome available. This distinction makes chromosome choice central to balancing X-linked gene expression between these cell types.
Research on the Xic connects chromosome-level gene regulation with epigenetic control, meaning regulation associated with chromatin state rather than changes to DNA sequence. It also helps explain how developmental signals establish an inactive X chromosome during embryogenesis. These insights clarify how cells achieve dosage compensation while adopting distinct chromosome states.
The Xic provides a framework for examining how an inactive X chromosome is handled when cells undergo reprogramming. Because its activity is tied to Xist expression, chromatin modification, and developmental chromosome states, researchers can use this system to investigate changes in epigenetic regulation during reprogramming and relate those changes to cellular developmental history.
Examining the Xic clarifies how regulation of an X chromosome can alter the overall pattern of X-linked gene expression. That regulatory context can inform studies of sex chromosome disorders and disease mechanisms involving X-linked genes. It also helps researchers interpret how chromosome choice, Xist activity, and transcriptional inactivation may contribute to disease-related differences between cells.