IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Multiple pathways for cholesterol signaling in Tetrahymena thermophila
Autor/es:
HERNANDEZ J; UTTARO AD
Lugar:
Mar del Plata
Reunión:
Congreso; LI Reunión anual de la SAIB; 2015
Resumen:
The free-living protozoon Tetrahymena thermophila does not require neither synthesize sterols. When sterols arepresent in the media they are incorporated and modified by desaturations at several positions. Desaturating enzymesare induced whereas the synthesis of the sterol surrogate ?tetrahymanol? is repressed. Tetrahymanol is completelydisplaced from the cell membranes by sterol derivatives. By RT-qPCR we evaluated the effect of cholesterol andknown effectors of canonical signaling pathways on the transcription of two reporter genes: C7-desaturase (Des7) andsqualene synthase (SqS), a key enzyme in tetrahymanol synthesis. Des7 and SqS transcripts were respectively, 2-foldinduced and 10-fold repressed after one hour of cholesterol addition, in agreement with our previous RNAseq results.8-Br-cAMP, wortmannin, PMA, BAPTA-AM and U73122 did not show significant effect on Des7 transcription,whereas Gö6976 slightly induced Des7. Interestingly, PMA alone repressed 10 fold SqS, suggesting the gene isdownregulated by cholesterol via PKC signaling. It was confirmed by using the PKC inhibitor Gö6976, whichabrogated the effect of cholesterol. Notably, BAPTA-AM and the PI-PLC inhibitor U73122 (1 and 10 uM) did notshow significant effect on SqS. These results and the proposed model suggest that Des7 and SqS are transcriptionallyregulated by two independent non-canonical pathways.