title: Differential gene expression in a marine sponge in relation to its symbiotic state.
abstract: The molecular mechanisms involved in the establishment and maintenance of sponge photosymbiosis, and in particular the association with cyanobacteria, are unknown. In the present study we analyzed gene expression in a common Mediterranean sponge (Petrosia ficiformis) in relation to its symbiotic (with cyanobacteria) or aposymbiotic status. A screening approach was applied to identify genes expressed differentially in symbiotic specimens growing in the light and aposymbiotic specimens growing in a dark cave at a short distance from the illuminated specimens. Out of the various differentially expressed sequences, we isolated two novel genes (here named PfSym1 and PfSym2) that were up-regulated when cyanobacterial symbionts were harbored inside the sponge cells. The sequence of one of these genes (PfSym2) was found to contain a conserved domain: the scavenger receptor cysteine rich (SRCR) domain. This is the first report on the expression of sponge genes in relation to symbiosis and, according to the presence of an SRCR domain, we suggest possible functions for one of the genes found in the sponge-cyanobacteria symbiosis.
authors.affiliation: Department of Plant Sciences, George S Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel. steindler@icgeb.org
authors.forename: Laura
authors.initials: L
authors.lastname: Steindler
authors.forename: Silvia
authors.initials: S
authors.lastname: Schuster
authors.forename: Micha
authors.initials: M
authors.lastname: Ilan
authors.forename: Adi
authors.initials: A
authors.lastname: Avni
authors.forename: Carlo
authors.initials: C
authors.lastname: Cerrano
authors.forename: Sven
authors.initials: S
authors.lastname: Beer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D000458:Cyanobacteria / Q000502:physiology; D004247:DNA / Q000737:chemistry; D020869:Gene Expression Profiling / Q000662:veterinary; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D047130:Petrosia / Q000235:genetics* / Q000382:microbiology* / Q000502:physiology; D016415:Sequence Alignment; D013559:Symbiosis / Q000235:genetics* / Q000502:physiology
chemical_list: D004247:DNA