X Inactivation Center

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...

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...

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...

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...

The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1. Types of Unit Cells Imagine taking a large number of identical...