In Aurelia aurita, applied iodine induces medusa formation (strobilation). This process also occurs when the temperature is lowered. This was found to increase oxidative stress resulting in an increased production of iodine from iodide. One polyp produces several medusae (initially termed ephyrae) starting at the polyp's oral end. The spreading of strobilation down the body column is controlled by a feedback loop: ephyra anlagen decrease the tyrosine content in adjacent polyp tissue by producing melanin from tyrosine. Endogenous tyrosine is able to remove iodine by forming iodiferous tyrosine compounds. The reduced level of tyrosine causes the ephyra-polypborder to move towards the basal end of the former polyp. We argue that an oxidant defence system may exist which makes use of iodide and tyrosine. Like other marine invertebrates, polyps of Aurelia contain iodide ions. Inevitably produced peroxides oxidise iodide into iodine. The danger to be harmed by iodine is strongly decreased by endogenous tyrosine which reacts with iodine to form iodiferous tyrosine compounds including thyroxin. Both substances together, iodide and tyrosine, form an efficient oxidant defence system which shields the tissue against damage by reactive oxygen species. In the course of evolution (from a species at the basis of the animal kingdom like Aurelia to a highly evolved species like man) the waste product thyroxin (indicating a high metabolic rate) has developed into a hormone which controls the metabolic rate.

High mobility group (HMG) proteins HMGI, HMGY, HMGI-C, and Chironomus HMGI are DNA-binding proteins thought to modulate the assembly and the function of transcriptional complexes. Each of these proteins contains three DNA-binding domains (DBD), properties of which appear to be regulated by phosphorylation. High levels of these proteins are characteristic for rapidly dividing cells in embryonic tissues and tumors. On the basis of their occurrence, specific functions for each of these proteins have been postulated. In this study we demonstrate differences in the nature of contacts of these proteins with promoter region of the interferon-␤ gene. We show that HMGI and HMGY interact with this DNA via three DBDs, whereas HMGI-C and Chironomus HMGI bind to this DNA using only two domains. Phos- Despite continuously increasing interest in the function(s) of this group of proteins, the nature of the interaction of these proteins with DNA is still not sufficiently understood. The proteins of the HMGI/Y family are 10 -11 kDa in size, are highly charged, are rich both in acidic and basic residues, are proline-rich, and contain only few residues with bulky hydrophobic side chains. This unusual amino acid composition inhibits folding of the polypeptide backbone of these proteins into any defined secondary structure. Common for HMGI/Y proteins is the presence of three putative DNA-binding domains (DBD), so called . NMR analysis of a complex of a peptide derived from HMGI(Y) bound to a short DNA fragment revealed that the centrally located RGR residues are essentially for binding and responsible for contacts of the protein with the bases and phosphate-sugar backbone (27). Alternative approaches, which used deletion and point-mutated proteins, revealed that two or three DBDs of the protein bind to DNA in a cooperative way (28 -30). Application of the protein-footprinting method for mapping of protein regions interacting with DNA (31) allowed more detailed characterization of the binding of HMGI(Y) proteins to DNA (32). A combination of this method

The autoimmune polyglandular syndrome (APS) is characterized by a variable coexistence of several autoimmune diseases, affecting predominantly endocrine glands. In general two types of APS are distinguished. Type 1 APS is an autosomal recessive disorder often leading to insufficiency of the adrenal cortex, the parathyroid glands, and/or the gonads. This type of APS often affects the skin in form of chronic mucocutaneous candidiasis and ectodermal dystrophies (vitiligo, alopecia, keratopathy, dystrophy of dental enamel and nails). The second form of APS is a polygenic disease which usually involves the adrenal gland, the thyroid and the pancreatic beta-cells. In rare cases APS type 2 is associated with myasthenia gravis, autoimmune thrombocytopenic purpura, Sjogren's syndrome or rheumatoid arthritis. Here we describe a case of APS with the unusual combination of type 1 diabetes, secondary adrenocortical insufficiency, growth hormone deficiency, and primary hypothyroidism associated with lethal idiopathic giant cell myocarditis. The combination of APS and idiopathic giant cell myocarditis which is a rare, frequently fatal autoimmune disorder of myocardium affecting most commonly young individuals has not been reported so far.

High-mobility group I/Y (HMGI/Y) proteins are chromosomal proteins involved in gene and chromatin regulation. Elevated levels of HMGI/Y proteins were reported in diverse malignant tumors, and rearrangements of their genes are casually involved in the development of benign tumors. In humans, the chromosomal locus Xp22 has been often found to be affected in diverse benign mesenchymal tumors. Recent studies revealed that this region contains a retropseudogene HMGIYL1 which potentially can be activated in a way of "exonization" upon aberrations involving this region. The coding sequence of the HMGIY-L1 is highly homologous to the HMGI(Y) gene. On the protein level, both HMGIYL1 and HMGI differ at few amino acid residues, including their putative DNA-binding domains (DBDs). Here we have approached the question of whether the HMGIYL1 product would be able to adopt a role of HMGI in the context of binding to gene promoters and chromatin. Comparative binding studies, employing protein footprinting technique, revealed that HMGIYL1 has lost the ability to bind to the promoter of the interferon beta gene, but retained its high affinity for the four-way junction DNA. Our results stress the importance of particular residues within the DBDs for DNA binding and demonstrate that tight binding of HMGI/Y proteins to the four-way junction DNA can be achieved in alternative ways. The binding of HMGIYL1 to four-way junction DNA suggests that activation of the HMGIYL1 gene would yield a protein sharing some binding properties with HMG1-box proteins and histone H1. Thus, the HMGIYL1 could interplay together with these components in chromatin regulation.

No abstract