INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
BIOCHEMICAL CHARACTERIZATION OF TCCYC6: A PROTEIN WITH CYCLIN HOMOLOGY FROM TRYPANOSOMA CRUZI
Autor/es:
AGOSTINA DI RENZO; MARÍA TERESA TELLEZ-IÑÓN; MARC LAVERRIERE; SERGIO SCHENKMAN; MARIANA POTENZA
Lugar:
Mar del Plata, Argentina
Reunión:
Congreso; X Congreso de Protozoología y Enfermedades Parasitarias; 2014
Institución organizadora:
Sociedad Argentina de Protozoología
Resumen:
The cell cycle is a highly regulated process that requires
Cyclin-Dependent Kinases (CDKs) in association with cyclins and other factors to activate or
inactivate biochemical pathways that leads to proper duplication and
segregation into new daughter cells. Which are these regulators controlling the
cell cycle in Trypanosoma cruzi, a
pathogen parasite that alters between proliferative and non dividing forms, is
still poorly understood and deserves further study. The genome of T. cruzi codify for ten sequences with
cyclin homology (TcCYC2 to TcCYC11), three of which were
characterized at functional level by our group (TcCYC2, TcCCY4 and TcCYC5). In order to further understand
the role of the cyclin family in the cell cycle control of this parasite, a sequence
with similarity to mitotic cyclins (TcCYC6),
was studied. For this purpose, we first raised polyclonal antibodies against a N-terminal
peptide of TcCYC6 protein. This
antibody was unable to detect the endogenous expression of TcCYC6 in epimastigotes either by western blot or
immunofluorescence microscopy. However, it was possible to isolate the TcCYC6 messenger RNA, indicating that this
gene is processed at least as mature transcript. Then, we cloned the TcCYC6 coding sequence fused to the Influenza
hemagglutinin tag HA (TcCYC6-HA),
into the inducible expression vector pTcINDEX.
Over expression of TcCYC6-HA causes
inhibition of epimastigote growth, although the cell cycle pattern of parasite
population is not compromise. In agreement with this, studies using
immunofluorescence microscopy did not reveal any cell cycle dependent
re-localization of this recombinant protein. However, results from treatment
with specific inhibitors and affinity chromatography suggested that TcCYC6-HA protein could be degraded by
proteasome pathway. Complementation assays suggested that TcCYC6-HA does not
complement the G1 cyclin deficiency in yeasts, although other functional
experiments are under way.