| Author/Editor | Černila, Boštjan | |
| Title | Izolacija, analiza in izražanje s steroidi inducibilnih genov za HSP70 v glivi Rhizopus nigricans | |
| Type | monografija | |
| Place | Ljubljana | |
| Publisher | Medicinska fakulteta | |
| Publication year | 1999 | |
| Volume | str. 67 | |
| Language | slo | |
| Abstract | Filamentous fungus Rhizopus nigricans responds to addition of various steroids with induction of steroid hydroxylation system. The function of this system is protection of organism against toxic effect of steroids on fungal growth. At the same time, steroid inducers also cause induction of UDP-glucose epimerase. The expression of this enzyme is influenced also by some well known stressors, such as heat shock and osmotic stress. The aim of this work was to check the hypothesis that addition of some steroids into the growth medium provokes a general stress response in R. nigricans, which is manifested by induction of stress proteins from the Hsp70 family, well characterized markers of stress response in different cells and organisms. Using a fragment of Hsp70 cDNA from algae Chlamydomonas reinhardtii as a heterologous probe, we isolated nine positive cDNA clones by screening a cDNA library, which was prepared from heat-shocked mycelia. We sequenced two cDNA clones numbered 2/3 and 20/2, which were each 2 kb in size. Comparison of their amino acid sequences with sequences contained in GenBank database proved, that we have isolated two cDNA clones encoding two different proteins from Hsp70 family. According to typical structural elements in their primary structure, both proteins could be cytosolic Hsp70 from the DnaK subfamily. So far, cDNA clones 2/3 and 20/2 represent the first two genes for Hsp70 proteins described in the fungal phylum Zygomycota. Expression of both Hsp70 genes in different growth conditions was studied by Northern hybridization of total RNA isolated from mycelia treated with potential stressors: addition of different steroids and some known stressors. We found out that addition of testosterone or deoxycorticosterone induced both Hsp70 genes whereas estrone, estradiol or progesterone had no effect on Hsp70 mRNA levels. (Abstract truncated at 2000 characters) | |
| Descriptors | RHIZOPUS STEROIDS CULTURE MEDIA HEAT-SHOCK PROTEINS 70 BLOTTING, NORTHERN TESTOSTERONE DESOXYCORTICOSTERONE ESTRONE ESTRADIOL PROGESTERONE RNA, MESSENGER GENE LIBRARY DNA, COMPLEMENTARY BASE SEQUENCE |