Increased Expression of Integrin and Receptor Tyrosine Kinase Genes During Autograft Fusion in the SpongeGeodia cydonium

Abstract

Recently cDNAs coding for cell surface molecules have been isolated from sponges. The molecules for a-integrin, galectin, and receptor tyrosine kinase (RTK), obtained from the marine sponge, Geodia c-vdonium, have been described earlier. In the present study also the cDNA for one putative P-integrin has been identified from G. cydonium. The deduced aa sequence comprises the characteristic signatures, found in other metazoan /3-integrin molecules; the estimated size is 95,215 Da. To obtain first insights into the molecular events which proceed during autograft fusion, the expressions of these genes were determined on transcriptional and translational level. The cDNAs as well as antibodies raised against the recombinant sponge proteins a-integrin, RTK and galectin were used and Northern blot experiments and immunocytochemical analyses have been performed. The results show that transcription of the two subunits of an integrin receptor as well as of the RTK are strongly upregulated after grafting; levels of > 10-fold have been determined in the fusion zone of the grafts after a 10 days incubation. Immunofluorescence studies of sections through the fusion zone support these data. In contrast the transcription of the gene encoding galectin is drastically downregulated after grafting. In a parallel series of experiments the level of the heat-shock protein-70 was determined and it was found that it remained unchanged after grafting. We conclude that integrin subunits and the RTK molecule are involved in self-self recognition of sponge.

Retinoid X receptor and retinoic acid response in the marine sponge Suberites domuncula

“…The sources of chemicals and enzymes used have been given previously Wimmer et al, 1999a;Krasko et al, 2000). The 'Cell Death Detection ELISA plus' kit and the PCR-DIG-Probe were from Roche (Mannheim, Germany), and all-trans retinoic acid and poly-L-lysine (Mr 30·000-70·000) from Sigma (Deisenhofen, Germany).…”

Sponge Bcl-2 homologous protein (BHP2-GC) confers distinct stress resistance to human HEK-293 cells

“…71 Polyclonal antibodies against rBHP2GC were raised in rabbits as described. 72 Purified rBHP2GC (3610 mg of protein) was injected; after 15-weeks serum was collected and the antibodies were prepared; 73 they are termed PoAb-BHP2GC. In control experiments 100 ml of the PoAb-BHP2GC were adsorbed to 50 mg of rBHP2GC (30 min; 48C) prior to its use.…”

Cyclosporin A Suspends Transplantation Reactions in the Marine SpongeMicrociona prolifera

“…In parabiotic grafting experiments it has been shown that the intraspecific variability of AFs rivals that of the vertebrate MHC; any two individuals rejecting each other have different genomic sequences for AF proteins as indicated by restriction fragment length polymorphism analysis (19,22). Other molecules involved in cell-ECM interactions such as ␣ and ␤ integrins and the hyaluronan receptor CD44 have been found to be differentially expressed in sponge isografts and allografts (7,23). Elevated integrin expression in the absence of appropriate ligands can promote apoptosis under otherwise permissive growth conditions (24).…”