Download The Mechanics of Life

Oklahoma State University
Institute for Agricultural Biosciences
• Approved and funded by the State legislature in 2006.
• Ground-breaking and construction was initiated in 2009
• Phase 1 completed in 2012. Phase 2 will be completed ?
Ins$tute for Agricultural Biosciences • Research facility for cellular and
molecular plant biology aimed at crop
improvement.
• Approximately 16,000 ft2 of laboratory,
office, and support space.
• Construction costs ~$16M.
• Projected annual budget ~$1M to $5M*.
*(Dependent on competitive research funding)
2 Faculty:
Randy D. Allen
Million Tadege
Todd Baughman
Professor, Director
Molecular Biology
Joined OSU in 2008
Associate Professor
Molecular Genetics
Joined OSU in 2009
Program Support Leader
Professor at Texas Tech
Post-doc at Wash U
Ph.D. - Texas A&M
M.S. - Univ. of Texas
Post-doc – SRNF,
CSIRO
Ph.D. – Univ. of Bern
M.S. - Wageningen
Agricultural Univ.
Professor and Extension
Specialist, Texas AgriLife
Ph.D. – Miss. State
M.S. – Oklahoma State
Weed Science
Joined OSU in 2011
3 Living Machines Cells are some$mes compared to factories Of course, cells are far more complex and self-­‐sustaining than any factory. For an accurate comparison, the factory would have to be able to build itself from scratch. Self-­‐replica$ng machines • Living things (organisms) are self-­‐replica$ng machines. • All organisms are composed of cells. • Most organisms consist of single cells. • Mul$cellular organisms are the most complex and integrated machines known. Cells • Cells are $ny self-­‐
replica$ng chemical factories. • Membranes isolate compartments for chemical reac$ons. • Allow for chemical and ionic gradients to be formed and maintained. • These gradients are used to generate chemical energy to do work. Proteins • Most of the work of a cell is accomplished by machines made of protein. • Proteins are long polymers of 20 different amino acids. • Each amino acid has a different chemical characteris$c. • Fold into 3-­‐dimensional shapes. • Act as catalysts, pores, pumps, motors, receptors, connectors and other structural elements. Complexity • A typical mammalian body is composed of: – 37 trillion cells. – 1 trillion in the brain alone. • About 100 billion of those are neurons. – More than 200 different types of cells. – Each cell contains 1 billion protein molecules. – About 100 thousand different kinds of protein. – About 30 thousand different genes that encode them. Energy • All of the work done in a cell requires energy. • Plants harvest solar energy to produce energy-­‐rich molecules. • This energy is used to “fix” carbon to produce all of the basic building blocks of life. • Animals derive their energy and fixed carbon by ea$ng plants and their products. Energy and electron carriers ATP carries chemical energy used to do cellular work. Enzymes that create ATP from ADP are called ATP synthases. Those that hydrolyze ATP for energy are Known as ATPases. NAD(P)H carries electrons to be used in Biosynthe$c reac$ons. Enzymes that Reduce NADP to NADPH are called ATP reductases. Those that oxidize NADPH to NADP are called oxidases or dehydrogenases. Photosynthesis Virtually all energy for life is derived from solar energy through photosynthesis ATP synthase Energy from proton concentra$on gradients is converted to chemical energy Flagellum motor Other motor proteins • Intracellular transport and movement depends on a network of protein scaffolding (cytoskeleton). • The proteins are dynamic and are constantly being assembled at one end and disassembled at the other. • Motor proteins that “walk” along these protein pathways to affect cell movement and carry cargo from one place to another. Cytoplasmic streaming Intracellular movement of organelles and other par$cles Vesicle trafficking in root hairs Transport of building materials to a construc$on site Kinesin motor proteins Walking proteins for intracellular transport of cargo Informa$on technology • All organisms store the informa$on to replicate themselves as a simple chemical code. • Informa$on is encoded by the precise sequence of subunits in a long polymer called deoxyribonucleic acid (DNA). • The code itself and the mechanisms to read and interpret the code are conserved in all organisms. DNA structure Informa$on storage molecules of the cell DNA replica$on Duplica$ng the recipes of life Central Dogma Transcrip$on and transla$on Building the tools and materials of life Gene$c code Human genome • Full genome sequences of humans contains more than 3 billion nucleo$des. • Humans, like most mammals, have about 30,000 different genes. • Coding sequences are highly conserved among related organisms. • Only about 5% of the genome is used to encode proteins (95% is noncoding). Gene regula$on • Cells in mul$cellular organisms have specialized func$ons. • All cells of an organism contain the same DNA (with some excep$ons). • Cellular specializa$on depends on differen$al expression of genes. • Some of this regula$on has to do with the way the DNA is packaged in chroma$n. Chroma$n Compact packaging of gene$c informa$on Chroma$n and gene regula$on DNA packaging affects gene expression Luciferase Forward genetics using pGSTF8::Luciferase
reporter
Arabidopsis Glutathione
S-transferase F8 (GSTF8)
(Chen et al. 1996, 1999)
Responsive to a range of
stresses and treatments:
• auxins
• hydrogen peroxide (H2O2)
• salicylic acid (SA)
Dr. Vijay Veerappan
pGSTF8
Luciferase
EMS
mutagenesis
Aberrant luminescence
Endogenous
GSTF8
GSTF8-LUC
Luciferase expression assay WT hsi2-­‐4 HSI2/HSL1 repress seed maturation gene
expression in seedlings
(Braybrook and Harada, 2008, Mendoza et al. 2008)
Transcriptome analysis of gce1and hsi2-4, hsl1 mutants
Modification of histone C-terminal tails affect gene
expression
• Acetylation of H3 and H4 and
methylation of H3K4 and
H3K36 are associated with
active gene expression.
• Methylation of H3K9 is
associated with DNA
methylation-dependent gene
silencing.
• Methylation of H3K27 is
associated with polycombdependent gene silencing.
• Many HSI2-suppressed
genes are enriched in
H3K27me3.
Disruption of HSI2 PHD domain alters histone H3 methylation
HSI2 and HSL1 may recruit co-repressors to silence
actively expressed genes
Questions and Discussion?
Collaborators: Vijaykumar Veerappan, Naichong Chen
Funding: OAES, Noble Foundation, Sitlington Foundation.