MHC Molecules of Cartilaginous Fishes

2014 ◽  
pp. 173-197 ◽  
Author(s):  
Simona Bartl ◽  
Masaru Nonaka
Keyword(s):  
Mhc Molecules ◽  
Cartilaginous Fishes

Electron microscopy analysis of degenerating pancreatic ß cells in transgenic mice expressing the MHC Class I antigen Dd

1990 ◽  
Vol 48 (3) ◽  
pp. 548-549
Author(s):  
T. A. Stewart ◽  
D. Liggitt ◽  
S. Pitts ◽  
L. Martin ◽  
M. Siegel ◽  
...  
Keyword(s):  
Type I Diabetes ◽  
Disease Process ◽  
Class Ii ◽  
Class I ◽  
Type I ◽  
Aberrant Expression ◽  
Mhc Molecules ◽  
Endogenous Insulin ◽  
Class Ii Mhc ◽  
Ifn Γ

Insulin-dependant (Type I) diabetes mellitus (IDDM) is a metabolic disorder resulting from the lack of endogenous insulin secretion. The disease is thought to result from the autoimmune mediated destruction of the insulin producing ß cells within the islets of Langerhans. The disease process is probably triggered by environmental agents, e.g. virus or chemical toxins on a background of genetic susceptibility associated with particular alleles within the major histocompatiblity complex (MHC). The relation between IDDM and the MHC locus has been reinforced by the demonstration of both class I and class II MHC proteins on the surface of ß cells from newly diagnosed patients as well as mounting evidence that IDDM has an autoimmune pathogenesis. In 1984, a series of observations were used to advance a hypothesis, in which it was suggested that aberrant expression of class II MHC molecules, perhaps induced by gamma-interferon (IFN γ) could present self antigens and initiate an autoimmune disease. We have tested some aspects of this model and demonstrated that expression of IFN γ by pancreatic ß cells can initiate an inflammatory destruction of both the islets and pancreas and does lead to IDDM.

MHC Sınıf I ve MHC Sınıf II Gen Düzenlenmesi

2020 ◽  
Vol 8 (3) ◽  
pp. 144-156
Author(s):  
Şule KARATAŞ ◽  
Fatma SAVRAN OĞUZ
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Gene Regulation ◽  
Mhc Class I ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Class I ◽  
Mhc Molecules ◽  
Class Ii Mhc ◽  
Regulation Mechanisms

Introduction: Peptides obtained by processing intracellular and extracellular antigens are presented to T cells to stimulate the immune response. This presentation is made by peptide receptors called major histocompatibility complex (MHC) molecules. The regulation mechanisms of MHC molecules, which have similar roles in the immune response, especially at the gene level, have significant differences according to their class. Objective: Class I and class II MHC molecules encoded by MHC genes on the short arm of the sixth chromosome are peptide receptors that stimulate T cell response. These peptides, which will enable the recognition of the antigen from which they originate, are loaded into MHC molecules and presented to T cells. Although the principles of loading and delivering peptides are similar for both molecules, the peptide sources and peptide loading mechanisms are different. In addition, class I molecules are expressed in all nucleated cells while class II molecules are expressed only in Antigen Presentation Cells (APC). These differences; It shows that MHC class I is not expressed by exactly the same transcriptional mechanisms as MHC class II. In our article, we aimed to compare the gene expressions of both classes and reveal their similarities and differences. Discussion and Conclusion: A better understanding of the transcriptional mechanisms of MHC molecules will reveal the role of these molecules in diseases more clearly. In our review, we discussed MHC gene regulation mechanisms with presence of existing informations, which is specific to the MHC class, for contribute to future research. Keywords: MHC class I, MHC class II, MHC gene regulation, promoter, SXY module, transcription

scholarly journals The Independent Evolution of Dorsal Pallia in Multiple Vertebrate Lineages

2021 ◽  
pp. 1-12
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
Olfactory Bulbs ◽  
Sensory Inputs ◽  
Independent Evolution ◽  
Sensory Modalities ◽  
Olfactory Input ◽  
Cartilaginous Fishes

Comparative neurobiologists have long wondered when and how the dorsal pallium (e.g., mammalian neocortex) evolved. For the last 50 years, the most widely accepted answer has been that this structure was already present in the earliest vertebrates and, therefore, homologous between the major vertebrate lineages. One challenge for this hypothesis is that the olfactory bulbs project throughout most of the pallium in the most basal vertebrate lineages (notably lampreys, hagfishes, and lungfishes) but do not project to the putative dorsal pallia in teleosts, cartilaginous fishes, and amniotes (i.e., reptiles, birds, and mammals). To make sense of these data, one may hypothesize that a dorsal pallium existed in the earliest vertebrates and received extensive olfactory input, which was subsequently lost in several lineages. However, the dorsal pallium is notoriously difficult to delineate in many vertebrates, and its homology between the various lineages is often based on little more than its topology. Therefore, we suspect that dorsal pallia evolved independently in teleosts, cartilaginous fishes, and amniotes. We further hypothesize that the emergence of these dorsal pallia was accompanied by the phylogenetic restriction of olfactory projections to the pallium and the expansion of inputs from other sensory modalities. We do not deny that the earliest vertebrates may have possessed nonolfactory sensory inputs to some parts of the pallium, but such projections alone do not define a dorsal pallium.

scholarly journals The Cerebellum and Cerebellum-Like Structures of Cartilaginous Fishes

2012 ◽  
Vol 80 (2) ◽  
pp. 152-165 ◽  
Author(s):  
John C. Montgomery ◽  
David Bodznick ◽  
Kara E. Yopak
Keyword(s):  
Cartilaginous Fishes

scholarly journals HLA-DQB1 codon 57 is critical for peptide binding and recognition.

1996 ◽  
Vol 183 (3) ◽  
pp. 1253-1258 ◽  
Author(s):  
W W Kwok ◽  
M E Domeier ◽  
M L Johnson ◽  
G T Nepom ◽  
D M Koelle
Keyword(s):  
Amino Acid ◽  
T Cell ◽  
Cell Clone ◽  
Peptide Binding ◽  
Class Ii ◽  
Binding Studies ◽  
Peptide Complex ◽  
Mhc Molecules ◽  
Hla Dq ◽  
T Cell Clone

The association of specific HLA-DQ alleles with autoimmunity is correlated with discrete polymorphisms in the HLA-DQ sequence that are localized within sites suitable for peptide recognition. The polymorphism at residue 57 of the DQB1 polypeptide is of particular interest since it may play a major structural role in the formation of a salt bridge structure at one end of the peptide-binding cleft of the DQ molecules. This polymorphism at residue 57 is a recurrent feature of HLA-DQ evolution, occurring in multiple distinct allelic families, which implies a functional selection for maintaining variation at this position in the class II molecule. We directly tested the amino acid polymorphism at this site as a determinant for peptide binding and for antigen-specific T cell stimulation. We found that a single Ala-->Asp amino acid 57 substitution in an HLA-DQ3.2 molecule regulated binding of an HSV-2 VP-16-derived peptide. A complementary single-residue substitution in the peptide abolished its binding to DQ3.2 and converted it to a peptide that can bind to DQ3.1 and DQ3.3 Asp-57-positive MHC molecules. These binding studies were paralleled by specific T cell recognition of the class II-peptide complex, in which the substituted peptide abolished T cell reactivity, which was directed to the DQ3.2-peptide complex, whereas the same T cell clone recognized the substituted peptide presented by DQ3.3, a class II restriction element differing from DQ3.2 only at residue 57. This structural and functional complementarity for residue 57 and a specific peptide residue identifies this interaction as a key controlling determinant of restricted recognition in HLA-DQ-specific immune response.

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