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MAR-SAR elements flank the rat hst70 gene transcription unit

100%

Widlak W., Widlak P.

Cellular and Molecular Biology Letters

2004

tom 09

nr 1

The rat hst70 gene is specifically expressed in spermatocytes and spermatids. This tissue-specific expression of the gene is primarily mediated through cis-acting elements located within the 0.4 kb segment upstream of the coding region, including two transcription initiation sites. Here, we study the 5’ and 3’ distal elements flanking the hst70 gene and find that they possess structural motifs characteristic of MAR/SAR elements, and exhibit enhanced affinities for nuclear matrix binding in vitro. Such elements bind efficiently to matrices from either the testis or the liver, i.e. tissues where the gene is either fully active or repressed, although one subfragment in the 5’ region was identified as exhibiting testis-specific interactions. Surprisingly, the activity of the CAT reporter gene was repressed in testis-transient transfection assays when the hst70 promoter sequences were extended into the 5’ MAR/SAR.

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

84%

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

Acta Biochimica Polonica

2003

tom 50

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.

Ograniczanie wyników

1 Acta Biochimica Polonica

1 Cellular and Molecular Biology Letters

2 Widlak W.

1 Benedyk K.

1 Glowala M.

1 Krawczyk Z.

1 Malusecka E.

1 Nakai A.

1 Scieglinska D.

1 Vydra N.

1 Widlak P.

1 2004

1 2003

Wyniki wyszukiwania

MAR-SAR elements flank the rat hst70 gene transcription unit

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