|
| |
|
| |
The
research of the MIFAB is focused on the Molecular Basis of
Cell Regulation and Function, offering a multidisciplinary
approach with a renewed potential for developing two deficient
areas: biomedical sciences and pathology of economically important
organisms.
Our research includes basic biological research and its applications
to pathology and to Chilean relevant industrial problems.
The participating investigators are professionally and scientifically
trained in different areas (chemistry, immunology, pharmacology,
cellular and molecular biology, medicine, biochemistry, physiology,
industrial biotechnology), and they are experienced in a wide
range of techniques and procedures (i.e. cell culture, subcellular
fractionation, light and electron microscopy, mass spectrometry
analysis, protein and lipid purification, recombinant DNA
technologies, carbohydrate analysis, bioinformatics, etc).
This diversity is one of the strengths of this group and has
resulted in collaborative, synergistic research incrementing
productivity, both in term of publications
and patents.
The main areas of Research at MIFAB are summarized below.
|
|
|
|
| |
|
 |
EXTRACELULAR
MATRIX AND REGULATION OF MUSCLE DEVELOPMENT |
|
|
| |
This
project is directed by Dr. Enrique Brandan and its
main goals the study of the molecular and cellular mechanisms
involved in skeletal muscle differentiation, muscle regeneration
following injury and in the pathology of Duchenne Muscular
Dystrophy (DMD). The focus is on the role of the Extracellular
Matrix (ECM) on these processes and skeletal muscle cell differentiation.
The onset and progression of the differentiation process are
controlled by a complex set of interactions between myoblasts
and their environment. The presence of the extracellular matrix
is essential for normal myogenesis. Among the areas under
study are linb bud for nation and duchenne skeletal muscle
dystrophy. |
|
|
| |
|
CELL
SIGNALING CELL DIFFERENTIATION AND LIPID HOMEOSTASIS |
|
|
| |
Dr.
Miguel Bronfman directs a research group interested in
understanding the role of PPARs (Peroxisome proliferator activated
receptors) in the regulation of cell differentiation and lipid
homeostasis. These ligand-activated receptors, from the nuclear
receptor super family, are involved in a number of diseases,
such as obesity, diabetes and cancer. They are targets of
peroxisome proliferators, a class on non-genotoxic carcinogens
including hypolipidemic drugs, plastizisers, pesticides and
other environmental contaminants, and of the thiazolendiones
antidiabetic drugs. Current research is focused on the identity
of PPAR physiological ligands, and their interaction with
other signaling pathways, and on their function in nerve cells. |
|
|
| |
|
REGULATION
OF CELL PROLIFERATION AND CANCER |
|
|
| |
Dr.
Luis Burzio´s main interests are centered on the
diagnostics of human and animal diseases. His research has
led to the discovery of a novel mitochondrial RNA which is
over expressed in proliferating normal cells and tumor cell
lines. Dr. Burzio and his group are using tranformed human
cells as a model to understand the process of malignant transformation.
Additionally, they have found that the expression of this
RNA transcript is an excellent marker for precocious or pre-cancer
cells. These findings are included as a claim in a patent
aplication, In addition, Dr. Burzio is collaborating with
other members of our Institute in the development of a vaccine
for the salmon pathogen P. Salmonis and in the use
of state of the art technology for the design of new diagnostic
kits for the detention of salmon pathogens. |
|
|
|
|
SIGNALING
CASCADES CONTROLLING OVIDUCTAL EGG TRANSPORT |
|
|
| |
The
group directed by Dr. Horacio Croxatto is studying
different aspects of gene expression in cells of the mammalian
oviduct in response to ovarian steroidal hormones. Dr. Croxatto
is interested in studying signaling cascades utilized by the
ovarian hormone estradiol in the nongenomic regulation of
oviductal egg transport in the rat. He is also interested
in understanding the involvement of immune responses in the
pathway through which, mating-associated signals, change the
mechanism of action of estradiol in the rat oviduct, from
a nongenomic to a genomic mode. |
|
|
| |
|
CELL
SURFACE BIOGENESIS AND DYNAMICS |
|
|
| |
Dr.
Alfonso González is
currently studying the mechanisms by which proteins are sorted
in the exocytic route of cells, regionalized at the plasma
membrane and eventually removed from the cell surface by endocytosis.
These mechanisms not only determinate and control the variety
of functions of the cell surface but also provide multiple
sources of dysfunctions leading to disease and potential locus
for disease management. In addition, as part of long standing
collaboration with rheumatologists, he described autoantibodies
that could have pathogenic roles acting at the cell surface
and/or the endocytic pathway. The fact that autoantibodies
primarily described against intracellular antigens in lupus
could have targets at the cell surface potentially involved
in the pathogenesis of the disease, provided the first clues
to explore more directly how neuronal function might be affected
by autoantibodies associated with lupus psychosis, a long-standing
problem. |
|
|
|
|
ROLE
OF ATP AND THE PURINORECEPTORS IN SYMPATHETIC COTRANSMISSION |
|
|
| |
The
main research focus of Dr. Juan Pablo Huidobro-Toro
is related to the cellular and molecular basis of sympathetic
co-transmission, which involves the concerted action of noradrenaline
(NA), neuropeptide Y (NPY) and ATP. Using a variety of vascular
neuroeffector junctions he demonstrated the mechanisms that
control release of NA and NPY form rat and human vascular
adrenergic nerve terminals. He showed that presynaptic receptor
control differentially the release of the large and the small
synaptic vesicle content. He hypothesized therefore that several
control mechanisms operate through presynaptic receptors,
to differentially control the mobilization of the synaptic
vesicles. He is studying the subtype of nucleotide receptors
involved in vascular sympathetic reflexes ant their intracellular
signaling mechanisms. Using molecular biology techniques and
pharmacological protocols, he is currently analyzing the expression
and functional properties of the adrenergic, serotonergic,
NPY, P2X and P2Y receptor subtypes localized in the endothelial
and/or smooth muscles from animal and human vascular biopsies
with or without pervascular sympathetic nerves. |
|
|
|
|
MOLECULES
AND MECHANISM IN ALZHEIMER'S DISEASE |
|
|
| |
Alzheimer's
disease (AD) is the main focus of Dr. N. C. Inestrosa's
research. His research has led to the view that common intraneuronal
signaling mechanisms should be involved in early Ab fibril
deposition, leading to the involvement of the Wnt signal transduction
pathway in AD. Dr. N. C. Inestrosa's group has described that
Ab-dependent neurotoxicity induces a loss of function of Wnt
signaling components (including an increase in: GSK-3b activity
, b-catenin degradation and target gene transcription), and
that compounds that mimic this signaling cascade may be putative
candidates for therapeutic intervention in Alzheimer's patients.
Recent studies using agonists of the M1 muscarinic receptor,
PPAR-g and PKC showed that they were able to prevent Ab neurotoxicity
by a mechanism that imply a cross-talk with the Wnt signaling
transduction pathway. In addition, Dr. Inestrosa´s group has
carried out studies on the neuropathological and behavioral
effect of amyloid deposits in animal models including the
Caenorhabditis elegans. Finally, the capacity of the APP and
the prion protein to protect against copper neurotoxicity
has been recently established. |
|
|
|
|
MOLECULAR
BIOLOGY OF ENVIRONMENTAL ADAPTATION |
|
|
| |
Dr.
Manuel Krauskopf's laboratory
studies the neuroendocrine cascade triggered by changes in
ambient temperature in eurythermal fish. This entails transcriptional
modulation in the hypothalamic-pituitary axis. Dr. Krauskopf
and his group were among the first to describe the molecular
mechanisms that govern the physiological adaptation of fish
to the cyclical changes of the environment showing that differential
gene expression plays a remarkable role in the underlying
mechanisms that produce the seasonal physiological acclimatization
in eurythermal ectotherms. More recently he has shown that
the pituitary gland is a central node in the transduction
of the physical parameters' stimulus into molecular signals.
His current studies relate to the role the pituitary gland
plays in the transduction of the physical parameters' stimulus
into molecular signals. His group has characterized the complete
carp Pit-1 genome, the first in a teleost, and corroborated
that the expression of this specific transcription factor
was indeed clearly articulated with the seasonal changes of
prolactin transcription. He was also the first to show that
seasonal acclimatization generates profound segregation of
the nucleolar components in the carp hepatocyte, which has
led to important advances in the understanding of the role
of ribosomal biogenesis in the temperature and photoperiod
adaptive process in eurythermal fish. In the field of Biotechnology,
they have approached the isolation of carp and Chilean sole
myostatin in order to obtain fish genetically modified to
increase their muscular mass. Currently progress is being
made to obtain recombinants containing the complete sequence
of Chilean sole myostatin cDNA. |
|
|
|
|
REGULATION
OF THE IMMUNE RESPONSE AT THE CELLULAR AND MOLECULAR LEVELS |
|
|
| |
The
role of dendritic cells on lymphocyte homing is at the center
of the research carried out at Dr. Mario Rosemblatt's
laboratory. Besides his work on T cell homing, his laboratory
is studying several aspects of dendritic cell biology, including
the production of cytokines by dendritic cell and the effect
of immunosuppressive drugs on their secretion as well as on
and human allotransplant acceptance. Another aspects being
investigated are the role of intracellular proteases (cathepsins)
on chemokine production and its effect on T cell homing and
the effect cytokine and chemokine environment on the development
of dendritic cells and in the Th1/Th2 polarization of the
immune response. |
|
|
|
|
GENOMICS
AND ITS APPLICATION TO INFECTIOUS DISEASES |
|
|
| |
As
mentioned early, one of the aims of this Institute is to bridge
the dramatic gap existing between the Chilean industrial sector
and recent development in the biological sciences. Several
applied projects are being led by Dr. Pablo D Valenzuela,
Head of MIFAB.
Red Tide. The general objective of this project is
the genomic study of Alexandrium catenella one of the microalgae
causing the Red Tide in Chile. The main aim is to generate
basic knowledge towards understanding the molecular biology
of this organism. The specific aims of the project, which
is being carried out in collaboration with the Livermore
National laboratory (www.llnl.gov
) in
California (USA) includes the generation and sequencing of
cDNA libraries of A. catenella together with the bioinformatic
( www.cgb.cl
)
analysis of these sequences, including annotation and classification
of the genes. We hope to identify genes relevant to cell division
and toxicity that may help in the understanding of the Red
Tide blooms.
Genomics of grapevine virus (www.genomicavides.cgb.cl)
This program, which is carried out in collaboration with Patricio
Arce ( www.bio.puc.cl/profs/arce
) from Universidad Católica and also with
Dr. Shauna Somerville from Stanford University. The project
is partially funded by the Chilean Plant Genome Program
(www.genomachile.cl)
and the Chilean Association of Fruit Exporters and involves
the isolation and sequencing of several isolates of grapevine
leafroll and fanleaf virus to establish their genetic variability
and to develop improved viral detection products. A longer
term goal is to produce viral resistant grapevines.
Molecular Biology and immunobiology of Hanta virus. Researchers
at the MIFAB and Fundación Ciencia para la Vida have initiated
genomic studies of the Andes variety of Hantavirus with the
purpose of developing rapid diagnostic tests and eventually
prepare a imunotherapeutic reagents that may be used for the
treatment of affected patients. The project involves sequencing
of the viral genome and the preparation of monoclonal and
polyclonal antibodies against mayor viral determinants that
may neutralize the virus. This project is a collaborative
effort with scientists from the Instituto de Salud Pública
de Chile.
Genomic and immunological studies
of salmon pathogens. In collaboration
with scientists from Incyte Genomics
(www.incyte.com)
MIFAB investigators have sequenced the 2 million base pair
genome of the salmon pathogen Piscirickettsia Salmonis. This
effort is part of a wider project aimed at studying several
pathogens affecting Chilean salmon industry. Our goal is to
develop sensitive detection methods and genetic or recombinant
vaccines against some of these pathogens. |
|
| |
|
|
|
GENETICS OF LIGNINOLYTIC ENZYMES OF FUNGI |
|
| |
Lignin is a complex aromatic polymer found in association with polysaccharides at the plant cell wall. Lignin structure, both stereo-irregular and amorphous, not only contributes to its uniqueness in nature but also offers new challenges in studies dealing with its biodegradation. In natural environments, the polymer is fragmented by free radicals produced by various types of peroxidases and phenol oxidases secreted by ligninolytic fungi. The low-molecular weight degradation intermediates produced are thereafter mineralized by bacteria and fungi. The attention of Dr Rafael Vicuña and collaborators is focused on the fungus Ceriporiopsis subvermispora, a white-rot basidiomycete highly aggressive and selective towards lignin when growing on wood. This microorganism produces isoenzyme families of manganese-dependent peroxidase and laccase, a copper-containing phenol oxidase. In addition to contribute to the understanding of the overall process of ligninolysis, our aim is to elucidate the meaning for this isoenzyme heterogeneity. For this purpose, we are studying the enzymological properties of these isoforms, as well as the structure and expression of the genes coding for them. Genomics studies are supported by the recently available genome of another basidiomycete called Phanerochaete Chrysosporium. We are particularly interested in the regulation of the expression of genes coding for lacase and manganese peroxidase by metals, aromatic compounds and agents that give rise to oxidative stress. We are also studying some physiological aspects of lignin decay, such as the role of some low-molecular weight metabolites secreted by C. subvermispora. |
|
|
|
| |
|
|
HISTOCOMPATIBILITY
ANTIGENS, NEW REGULATORY IMMUNE MECHANISMS |
|
|
| |
One
the main aims of Dr. María Rosa Bono's research concerns the
endothelium of secondary lymphoid organs, which is specifically
adapted for the free crossing of lymphocytes, a crucial step
in the initiation of the adaptive immune response. Using a
model of human endothelial cells from human lymphoid organ
they have found that direct contact of B cell lines (but not
T cells) resulted in changes in the phosphorylation state
of endothelial cells causing their functional activation.
Her group is also studying a non-classical expression of MHC
class II molecules on the endothelial cells produced after
contact of B cells as well as the classical mechanism of expression
of MHC class II molecules, in particular the participation
of the CIITA protein in this mechanism |
|
|
|
|
GENOMICS
OF RALSTONIA EUTROPHA AND DEGRADATION OF ENVIRONMENTAL POLLUTANTS |
|
|
| |
The
main focus of Dr. Bernardo González's work is the understanding
of the molecular basis for the high catabolic ability of the
well-known soil bacterium Ralstonia eutropha JMP134 (pJP4)
to degrade diverse (chloro)aromatic pollutants. Recent work
deals with the study of the effect of the acquisition (by
lateral gene transfer) of new catabolic genes, the key effect
that these genes play in the catabolic performance of this
bacterium, and the complex role of the enzyme maleylacetate
reductase in catabolism of mono, di and trichlorinated aromatic
compounds. Sequencing the complete genome of R. eutropha JMP134
has been carried out based on a DOE/JGI, University of California
/ Fundación Ciencia para la Vida / MIFAB and FCB-PUC initiative.
This has made available a first draft of the genome. We have
completed the annotated sequence of the catabolic pJP4 plasmid
showing the presence and activity of mobile elements in the
plasmid, and the ability of these plasmid elements to mediate
acquisition of chromosomal sequences. This study has also
provided new clues on the evolution of this catabolic plasmid,
and therefore, the mechanism of bacterial adaptation to degrade
pollutant compounds. |
|
|
|
|
STUDIES
OF THIOBACILLUS FERROOXIDANS AND BIOMINING |
|
|
| |
Biominning
has been one of the main interests of Dr. David Holmes for
many years. The highlight of the year was the completion of
the annotation of the genome of Acidithiobacillus ferrooxidans
using DNA sequence information provided by Integrated Genomics
(IG) and The Institute for Genome Research (TIGR). The annotation
required the use of automatic programs for ORF finding (ARTEMIS),
gene identification (various BLAST and HIDDDEN MARKOV MODEL
programs) and the display of the results in an interactive
and user-friendly form (ARTEMIS). Students learnt the use
of these programs and wrote BIOPEARL scripts to connect the
various modules permitting automated annotation. Such programs
are now installed in a unix based server and, one of the chief
advantages, is that they can now be used for the automated
annotation of additional genomes that might be of interest
to other members of the MIFAB or the scientific community
at large.
In addition to automatic analysis, the annotation of a genome
also requires human intervention to correct simple errors
of ORF finding and to provide a more profound analysis of
gene identification and gene function. Students have been
involved in learning techniques that accomplish these objectives.
Finally, the major goal of annotation is to provide information
that can be applied to solving biological problems, including,
interalia, metabolic modeling, prediction of protein-protein
interaction and the construction of gene regulatory networks.
Students have used the A. ferrooxidans annotation to build
metabolic models of relevance to the biotechnology application
of the organism in mineral recovery. They have presented their
findings at various national meetings and have recently submitted
three papers. They are currently carrying out biochemical
and genetic experiments to validate their bioinformatics models.
The annotation has also permitted us to design oligomers for
every predicted gene that we will use in the coming year to
carry out microarray analysis of gene transcription of A.
ferrooxidans grown under various conditions of interest to
the biomining community. One of my student won an American
Society for Microbiology scholarship to go to Amersham Inc,
California in 2003 to do the microarray experiments. |
|
| |
|
|
|
THE PLANT BIOTECHNOLOGY CENTER FOR ARID ZONES |
|
| |
Inserted in the Azapa valley (Agronomy Department), the new Center of Plant Biotechnology for Arid Zones promises to catalyze some radical improvements in farming practices in this region. The Center was created through collaboration between Tarapacá University and our Institute and is under the direction of Dr. Juan Pablo Sánchez. The Center research will concentrate in the understanding of the molecular mechanism that determines the drought, salt and boron tolerance. In addition the Center will develop applications of these research to create new and improve transgenic plants tolerant to these stresses.
Mainly, the two lines of research of the Center will be the understanding of drought stress response and boron toxicity tolerance and, will be approached by:
i) Physiology studies of toxicity and tolerance
ii) Study of mechanisms of transport across cellular membranes and over long distances in plant.
iii) Survey of genes whose expression is regulated by stress. Microarray studies
iv) Mutational analysis of components that determine tolerance and signaling of the stress response.
We hope that these advances will not only benefit agriculture within the region, but provide the development of expertise and new transgenic crops that will aid agricultural and economic growth throughout the rest of the country. |
|
|
|
|
GENE
CHANGES DURING ENVIRONMENTAL ADAPTIVE RESPONSES |
|
|
| |
To
advance our knowledge on the molecular mechanisms that govern
the adaptive response that environmental changes trigger in
eurythermal fish, Dr. Maria Inés Vera and her group are studying
the molecular consequences of physiological nucleolar segregation.
Presently, Dr. Vera's leads a research team working the characterization
of the molecular events leading to a down regulation of ribosomal
biogenesis during adaptive response to cold temperatures in
fish. Pursuing this line of work Dr. Vera's group has been
the first to demonstrate that nucleolin is involved in rRNA
synthesis reduction, and that the occurring physiological
nucleolar segregation constitutes a novel model in the study
of nuclear and nucleolar dynamics. Dr. Vera is currently continuing
this line of work collaborating with Dr. Philip Bouvet, (Lyon,
Francer), Dr. Jean Pierre Bachellerie (Toulouse, France) and
Marc Thiry, (Liege, Belgium). |
|
|
|
|
|
