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Identification of microsatellite region composed of a long homopurine-homopyrimidine tract surrounded by AT-rich sequences upstream of the rat stress-inducible hsp70.1 gene

100%

Lisowska K. , Loch T. , Fiszer-Kierzkowska A. , Scieglinska D. , Krawczyk Z.

nr 1

A DNA region containing several repetitive motifs has been detected about 1.9 kbp upstream of the transcription unit of the rat stress-inducible hsp70.1 gene. The most interesting element of this area is a microsatellite sequence (GA)eCAG(TC)24 that consists of an inverted repeat partially overlapping with the long homopurine/homopyrimidine tract (Pu/Py). DNA molecule within the described sequence can theoretically adopt alternate, non-B structures (H-DNA or cruciform) containing single-stranded regions. This microsatellite region is flanked by AT-rich sequences containing several poly(A) tracts. The longest of them with a possible potential to destabilize a double-stranded DNA helix is localized around 160 bp downstream the (GA)6CAG(TC)24. The DNA fragment containing sequences described above was subcloned into the pUCl9 vector and the resulting plasmid was subjected to the standard SI susceptibility assay. Preliminary mapping of the SI cleavage site indicates for the formation of the non-B-DNA structure within the Pu/Py tract. This is to our knowledge a first report on the existence of a complex microsatellite region upstream the 5'-end of the hsp70 gene in mammals.

Transcriptional active heat shock factor 1 (HSF1) leads to seminiferous epithelium degeneration in mice testes

86%

Vydra N. , Malusecka E. , Glowala M. , Benedyk K. , Scieglinska D. , Krawczyk Z. , Widlak W.

nr Supplement 1

Using of transgenic mice to study of 70-kDa heat shock protein family genes expression in testes

86%

Widlak W. , Vydra N. , Scieglinska D. , Malusecka E. , Fiszer-Kierzkowska A. , Glowala M. , Krawczyk Z.

nr 1

Expression of a constitutively active mutant of heat shock factor 1 under the control of testis-specific hst70 gene promoter in transgenic mice induces degeneration of seminiferous epithelium

72%

Widlak W. , Benedyk K. , Vydra N. , Glowala M. , Scieglinska D. , Malusecka E. , Nakai A. , Krawczyk Z.

nr 2

Heat shock activates in somatic cells a set of genes encoding heat shock proteins which function as molecular chaperones. The basic mechanism by which these genes are activated is the interaction of the specific transcription factor HSF1 with a regulatory DNA sequence called heat shock element (HSE). In higher eukaryotes HSF1 is present in unstressed cells as inactive monomers which, in response to cellular stress, aggregate into transcriptionally competent homotrimers. In the present paper we showed that the expression of a transgene encoding mutated constitutively active HSF1 placed under the control of a spermatocyte-specific promoter derived from the hst70 gene severely affects spermatogenesis. We found the testes of transgenic mice to be significantly smaller than those of wild-type males and histological analysis showed massive degeneration of the seminiferous epithelium. The lumen of tubules was devoid of spermatids and spermatozoa and using the TUNEL method we demonstrated a high rate of spermatocyte apoptosis. The molecular mechanism by which constitutively active HSF1 arrests spermatogenesis is not known so far. One can assume that HSF1 can either induce or repress so far unknown target genes involved in germ cell apoptosis.