IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Transcriptional regulation of the gene encoding lipoyl synthase in Bacillus subtilis
Autor/es:
MARTIN, N.; DE-MENDOZA, D.; MARIA CECILIA MANSILLA
Lugar:
Rosario
Reunión:
Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006
Resumen:
Lipoic acid (1,2-dithiolane-3-pentanoic acid) is a sulfur-containing
cofactor essential for function of several key enzymes involved in
oxidative metabolism. The biosynthetic pathway of this important
cofactor is poorly understood in Bacillus subtilis. It was recently
demonstrated in our laboratory that yutB codes a lipoyl synthase
in B. subtilis, so the gene was renamed lipA. The aim of the
present work was to study the regulation of this gene under
different growth conditions. This was accomplished by monitoring
the expression of PlipA-lacZ transcriptional fusions and assaying
â-galactosidase activity. The results indicate that lipA expression
is repressed during growth on poor sulfur sources, such as
glutathione and sulphate, and increased in the presence of
methionine. We also found out that lipA expression was
temperature-dependent: a decrease in growth temperature
induces the expression of the gene. In order to determine the
involvement of the B. subtilis two component system DesK-DesR
and its homologous YvfT-YvfU in the temperature-dependent lipA
expression, we analyzed the expression in mutants in ∆desKR,
∆yvfTU and in both systems. We observed that the temperature
regulation of lipA expression is not modified in these mutants. In
addition, in order to characterize the lipA promoter we are
performing primer extension experiments to map the transcription
initiation site.