INVESTIGADORES
GRAMAJO Hugo Cesar
artículos
Título:
The atf2 gene is involved in triacylglycerol biosynthesis and accumulation in the oleaginous Rhodococcus opacus PD630.
Autor/es:
HERNÁNDEZ MA, ARABOLAZA A, RODRÍGUEZ E, GRAMAJO H, ALVAREZ HM
Revista:
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2012 vol. 97 p. 2119 - 2130
ISSN:
0175-7598
Resumen:
Abstract Rhodococcus opacus PD630 is an oleaginous bacterium
able to accumulate large amounts of triacylglycerols
(TAG) in different carbon sources. The last reaction for TAG
biosynthesis is catalyzed by the bifunctional wax ester synthase/
acyl-CoA:diacylglycerol acyltransferase (WS/DGAT)
enzymes encoded by atf genes. R. opacus PD630 possesses
at least 17 putative atf homologous genes in its genome, but
only atf1 and atf2 exhibited a significant DGAT activity when
expressed in E. coli, as revealed in a previous study. The
contribution of atf1 gene to TAG accumulation by strain
PD630 has been demonstrated previously, although additional
Atfs may also contribute to lipid accumulation, since the atf1-
disrupted mutant is still able to produce significant amounts of
TAG (Alvarez et al., Microbiology 154:2327?2335, 2008). In
this study, we investigated the in vivo role of atf2 gene inTAG
accumulation by R. opacus PD630 by using different genetic
strategies. The atf2-disrupted mutant exhibited a decrease in
TAG accumulation (up to 25?30 %, w/w) and an approximately
tenfold increase in glycogen formation in comparison
with the wild-type strain. Surprisingly, in contrast to single
mutants, a double mutant generated by the disruption of atf1
and atf2 genes only showed a very low effect in TAG and in
glycogen accumulation under lipid storage conditions. Overexpression
of atf1 and atf2 genes in strain PD630 promoted an
increase of approximately 10 % (w/w) in TAG accumulation,
while heterologous expression of atf2 gene in Mycobacterium
smegmatis caused an increase in TAG accumulation during
cultivation in nitrogen-rich media. This study demonstrated
that, in addition to atf1 gene, atf2 is actively involved in TAG
accumulation by the oleaginous R. opacus PD630.