Gaye Lynn Wilson

RGS13 Regulates Germinal Center B Lymphocytes Responsiveness to CXC Chemokine Ligand (CXCL)12 and CXCL13

Normal lymphoid tissue development and function depend upon directed cell migration. Providing guideposts for cell movement and positioning within lymphoid tissues, chemokines signal through cell surface receptors that couple to heterotrimeric G proteins, which are in turn subject to regulation by regulator of G protein signaling (RGS) proteins. In this study, we report that germinal center B lymphocytes and thymic epithelial cells strongly express one of the RGS family members, RGS13. Located between Rgs1 and Rgs2, Rgs13 spans 42 kb on mouse chromosome 1. Rgs13 encodes a 157-aa protein that shares 82% amino acid identity with its 159-aa human counterpart. In situ hybridization with sense and antisense probes localized Rgs13 expression to the germinal center regions of mouse spleens and Peyer’s patches and to the thymus medulla. Affinity-purified RGS13 Abs detected RGS13-expressing cells in the light zone of the germinal center. RGS13 interacted with both Giα and Gqα and strongly impaired signaling through Gi-linked signaling pathways, including signaling through the chemokine receptors CXCR4 and CXCR5. Prolonged CD40 signaling up-regulated RGS13 expression in human tonsil B lymphocytes. These results plus previous studies of RGS1 indicate the germinal center B cells use two RGS proteins, RGS1 and RGS13, to regulate their responsiveness to chemokines.

Molecular mechanisms regulating CD19, CD20 and CD22 gene expression.

The CD19, CD20 and CD22 genes encode transmembrane proteins that are of vital importance to B-cell function. Similar to the immunoglobulin (Ig) genes, they are expressed in a lineage-specific and developmentally regulated manner. Here, John Kehrl and colleagues describe how an understanding of the transcriptional regulation of the CD19, CD20 and CD22 genes is leading to valuable insights into some of the important molecular events that occur in B-cell development and differentiation.

Evolutionary aspects of the endocrine and nervous systems.

Publisher Summary This chapter illustrates the evolutionary aspects of the endocrine and nervous systems. In mammals and other vertebrates, the major systems of intercellular communication are the endocrine and nervous systems. Intercellular communication is not unique to organisms which possess endocrine and nervous systems; rather it is essential to all forms of life including microbes. In the classic concept of the endocrine system the chemical messenger molecule, the hormone, is produced in a localized region, released into the general circulation, and acts on a target cell at a distance. In the nervous system, on the other hand, the secretory cell is a neuron and the messenger molecule a neurotransmitter. Many of the messenger molecules assigned to the endocrine or nervous systems reach their target tissues by other systems of intercellular communication such as exocrine and paracrine systems. Furthermore, a number of nonhormonal peptides which act on a target tissue have structural similarities to classic hormones and act on the target tissues in a manner almost identical to hormones. Interestingly, the biochemical elements necessary for the intercellular communication, that is, messenger molecules, their receptors, as well as post receptor intracellular components, are present in unicellular organisms and show distinct structural and functional similarities to their counterparts in vertebrate tissues.

Skunks have gene sequences in their cellular DNA related to squirrel monkey retrovirus: Transmission between species of a New World primate endogenous type D retrovirus

Abstract The squirrel monkey ( Saimiri , sciureus ), a New World primate, contains multiple copies of endogenous type D retroviral gene sequences in the cellular DNA of all its tissues. Gene sequences partially homologous to these type D virus genes are also found in the cellular DNA of normal tissues of the New World carnivore, the skunk ( Mephitis , mephitis and Spilogale , putorius ). We there-fore conclude that this class of viruses has, under natural conditions, been transmitted between the germ lines of these evolutionarily distant species. The example of interspecies transmission described here is the first that has been described among New World species and also the first that has been demonstrated for retroviruses other than type C viruses.