Cloning of a heat-inducible biomarker, the cDNA encoding the 70 kDa heat shock protein, from the marine sponge Geodia cydonium: response to natural stressors

The b~omarker concept lnvolves the use of biochemical, cellular and phys~ological parameters a s screening tools In environmental surveillance Stress protelns, such as heat shock protelns (HSPs), fulflll many of the requirements for belng Ideal candidates In a b~omarke r strategy for envlronmental monitonny Sponges (Porifera) are one of the major phyla tound in the m a n n e hard-substrate benthos, both w ~ t h respect to the number of s p e c ~ e s and b ~ o m a % s However, only recently have genes from sponges been cloned Here we describe the ~solatlon of the cDNA encodlng a heat shock protein of M, (relative molecular welght) 70 kDa (HSP70) The cDNA H5P70 from the marlne sponge Ceod~a cj~donlum has a length of 2 3 kb and encodes an AA sequrnce of M, 72 579 The sponge HSP70 dlsplays characterlstlc features of the HSP70 famlly The HSP70 proteln 1s Induced by natural stressors ~ncludlng changes In tempelature as well as pH, as demonstrated by Western blot analysls No response was observed after treating the samples with hypotonic or hypertonlc conditions Our results p rov~de the first molecular evldence that HSP7O of sponges 1s a useful blomarker