ANNUAL REPORT - Department of Biotechnology

A study was implemented at NCCS, Pune to
delineate the role of insulin in regulating the
expression of IGFBP-1 in the context of active
hypoxia inducible factor (Hif1). The hypothesis is
that insulin plays a dual role in the regulation of
Insulin-Like Growth Factor Binding Protein 1
(IGFBP-1). IGFBP-1 gene expression is positively
regulated by hypoxia and negatively by insulin. The
scientists have cloned the 1.5 kb upstream
sequence of IGFBP-1 promoter in the luciferase
reporter gene and have generated various deletion
fragments to analyse promoter activity in the
presence of insulin and iron chelators. They have
also cloned the 300 bp intron1 fragment containing a
putative Hif1 site in the luciferase reporter vector to
analyse the role of Hif 1 in insulin mediated activation
of IGFBP1.
A novel non-apoptotic cell death has been recently
identified which is designated as paraptosis. The
hallmark features of paraptotic cell death are
cytoplasmic vacuolization, mitochondrial swelling,
and absence of caspase activation and
oligonucleosomal DNA fragmentation. Absence of
caspases makes Dictyostelium discoideum a good
model system to study the role of Poly (ADP-ribose)
polymerase (PARP) in caspase independent cell
death mechanism. Studies done at JNU, New Delhi
suggest that Dictyostelium discoideum under
oxidative stress exhibits PARP mediated caspase
independent paraptotic cell death.
Computer Modelling, Simulation and
Optimization
A project is being implemented at IIT, Kharagpur to
understand the structure and interaction between
Rv0600c/Rv0601c/ Rv0602c proteins from M.
tuberculosis. In silico molecular model of Rv0600c
showed a typical kinase catalytic domain, with a well
conserved ATP binding site. The histidine kinases
were cloned into E.coli expression vector pQE30,
overexpressed and purified. Their secondary
structure was analysed by circular dichroism and
that confirmed the molecular models generated.
DBT Annual Report 2006-07
100
Molecular Immunology
Studies were carried out at IISc, Bangalore to
understand the trafficking of salmonella in dendritic
cells and its implication in antigen presentation. The
data elucidates a very potential role of intracellular
tolls like TLR9 in the pathogenesis of salmonella and
might be modulating the trafficking and antigen
presentation of salmonella. Studies are underway to
elucidate how TLR9 can modulate the trafficking and
presentation of salmonella in dendritic cells.
The Toll-like receptors (TLRs) represent a group of
single-pass transmembrane receptors conserved
from Drosophila to mammals, expressed on sentinel
cells, which are central to the innate immune
response and responsible for sensing microbial
products to trigger an antimicrobial response. The
studies carried out at Bose Institute, Kolkata
revealed how a virulence factor of the pathogenic M.
tuberculosis is able to trigger signaling processes
which dampen TLR-dependent proinflammatory
signals. They also raise the possibility of using ESAT-
6 or peptides derived from it as potential modulators
which may dampen prolonged undesirable
inflammatory signalling associated with conditions
such as sepsis.
Gene Cloning and Biochemical Characterization
Studies were carried out JNU, New Delhi for
understanding the initial steps in the
Glycosylphosphatidylinositol (GPI) biosynthesis
pathway in Candida albicans GPI anchored proteins
in C. albicans are essential for morphogenesis,
virulence, and adhesion of the fungal cells to their
host cells.
Amino acid sequences for PIG-A of Sachromyces
cerevisiae, Homo sapiens and putative Candida
albicans were analysed. Candida albicans, and
Sacchromyces cerevisiae possess 56% identity
while Candida albicans and, Homo sapiens has 46%
identity.
Very long chain fatty acids (VLCFA) represent 30% of
the total fatty acids in some tissues like retina, lens