Expression of one sponge Iroquois homeobox gene in primmorphs from Suberites domuncula during canal formation.
Sponges (Porifera) represent the evolutionary oldest multicellular animals. They are provided with the basic molecules involved in cell-cell and cell-matrix interactions. We report here the isolation and characterization of a complementary DNA from the sponge Suberites domuncula coding for the sponge homeobox gene, SUBDOIRX-a. The deduced polypeptide with a predicted Mr of 44,375 possesses the highly conserved Iroquois-homeodomain. We applied in situ hybridization to localize Iroquois in the sponge. The expression of this gene is highest in cells adjacent to the canals of the sponge in the medulla region. To study the expression of Iroquois during development, the in vitro primmorph system from S. domuncula was used. During the formation of these three-dimensional aggregates composed of proliferating cells, the expression of Iroquois depends on ferric iron and water current. An increased expression in response to water current is paralleled with the formation of canal-like pores in the primmorphs. It is suggested that Iroquois expression is involved in the formation of the aquiferous system, the canals in sponges and the canal-like structures in primmorphs.
Perović
Sanja
S
Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Duesbergweg 6, D-55099 Mainz, Germany. wmueller@mail.uni-mainz.de
Schröder
Heinz C
HC
Sudek
Sebastian
S
Grebenjuk
Vladislav A
VA
Batel
Renato
R
Stifanić
Mauro
M
Müller
Isabel M
IM
Müller
Werner E G
WE
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D016000:Cluster Analysis; D017931:DNA Primers; D005290:Ferric Compounds / Q000378:metabolism; D020869:Gene Expression Profiling; D005801:Genes, Homeobox / Q000235:genetics*; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010802:Phylogeny; D011161:Porifera / Q000033:anatomy & histology* / Q000235:genetics*; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D005290:Ferric Compounds