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(22-23) An inducible intron-containing hsp70-gene in the diplopod Tachypodoiulus niger? Knigge, Thomas*,1, Bachmann, Lutz2, Köhler, Heinz-R.1, 1 Animal Physiological Ecology, University of Tübingen, Konrad-Adenauer-Str. 20, Tübingen, Germany2 Zoological Museum, University of Oslo, Sars gate 1, Oslo, Norway ABSTRACT- Heat shock genes are classified as inducible hsps and constitutively expressed hscs (heat shock cognates). Due to their evolutionary elimination based on increased error rates in pre-mRNA splicing under elevated temperature or otherwise proteotoxic conditions, it is supposed that inducible heat shock genes do not contain introns. We have examined the consensus region of the hsp70 gene(s) in a number of soil invertebrate species of slugs, isopods, collembola, and diplopods using PCR. Primers have been designed to amplify a 550bp fragment using genomic or copy DNA. PCR products have been cloned and sequenced. All sequences could be aligned to hsps or hscs of other phyla. In two cases (one diplopod, one collembolan) products larger than 550bp were obtained if genomic DNA was utilized for PCR. In the diplopod Tachypodiulus niger PCR produced a fragment of 700bp. Smaller fragments could not be detected. As verified by RT-PCR, this 700bp genomic fragment contains introns and according to the above mentioned theory would be classified as a heat shock cognate (hsc70). However, our results suggest the gene of T. niger to be inducible by heat shock even though it contains introns. Moreover, there seems to be only one type of hsp70 in T.niger (whose gene products may be transcriptionally or translationally modified), apparently presenting an exceptional form. Quantitative RT-PCR and phylogenetic analyses were performed in order to gain further knowledge on T. niger hsp70. Key words: stress proteins, heat shock genes, millipedes, phylogeny |
