viernes, 25 de marzo de 2016

JCVI- syn3.0: Minimal Synthetic Bacterial Cell Constructed


THE FIRST MINIMAL SYNTHETIC BACTERIAL CELL IS CONSTRUCTED
Researchers from the J. Craig Venter Institute (JCVI) and Synthetic Genomics, Inc. (SGI) have accomplished the next feat in synthetic biology research—the design and construction of the first minimal synthetic bacterial cell, JCVI-syn3.0.

Using the first synthetic cell, Mycoplasma mycoides JCVI-syn1.0 (created by this same team in 2010), JCVI-syn3.0 was developed through a design, build, and test (DBT) process using genes from JCVI-syn1.0. The new minimal synthetic cell contains only 531,000 base pairs and just 473 genes making it the smallest genome of any self-replicating organism.


A paper describing this research is published in the March 25 print version of the journal, Science by lead author Clyde A. Hutchison, III, Ph.D., senior author J. Craig Venter, Ph.D., and senior team of Hamilton O. Smith, MD, Daniel G. Gibson, Ph.D., and John I. Glass, Ph.D.

J. Craig Venter, Ph.D., Dr. Hamilton O. Smith, M.D., Dan Gibson, Ph.D., Lijie Sun, Ph.D., John Glass, Ph.D., Krishna Kannan, Ph.D., John Gill, and Dr. Clyde A. Hutchison III, Ph.D. Credit: J. Craig Venter Institute

Writing Biological Code
A biological cell is very much like a computer—the genome is the software that encodes the instructions of the cell and the cellular machinery is the hardware that interprets and runs the genome software. Major advances in DNA technologies have made it possible for biologists to now behave as software engineers and rewrite entire genomes to program new biological operating systems.

Project Goals
A major goal in synthetic biology is to have the capacity to predictably design and build DNA that produces a cell with new and improved biological functions that do not already exist in nature. Significant advances have been made in DNA design at the gene and pathway level and in engineering bacteriophage genomes. But, even with all the advances that have been made in genomics and synthetic biology, there is still not a single self-replicating cell in which we understand the function of every one of its genes. Toward this goal, the JCVI/SGI team has been working to understand the gene content of a minimal cell—a cell that has only the machinery necessary for independent life.

Since the generation of the first synthetic cell in 2010, the team found ways to drastically speed up the process of building cells from the bottom up. They developed new tools and semi-automated processes for genome synthesis, including more rapid, more accurate, and more robust methods for going from oligonucleotides (small pieces of DNA) to whole chromosomes. Over the past 10 years whole bacterial chromosome assembly has gone from impossible, to possible in years, to months and now to just weeks with these new methods, which are made available to scientists in this manuscript.

A major outcome of this minimal cell program has been new tools and semi-automated processes for whole genome synthesis. Many of these synthetic biology tools and services are commercially available through SGI-DNA.

THE FIRST MINIMAL SYNTHETIC BACTERIAL CELL IS CONSTRUCTED
J. Craig Venter, Ph.D., Dr. Hamilton O. Smith, M.D., Dan Gibson, Ph.D., Lijie Sun, Ph.D., John Glass, Ph.D., Krishna Kannan, Ph.D., John Gill, and Dr. Clyde A. Hutchison III, Ph.D.  Credit: J. Craig Venter Institute. Download: High Resolution JPEG
J. Craig Venter, Ph.D. and Hamilton O. Smith, M.D.  Credit: J. Craig Venter Institute. Download: High Resolution JPEG
Hamilton O. Smith, M.D. and Clyde A. Hutchison III, Ph.D.  Credit: J. Craig Venter Institute Download: High Resolution JPEG
J. Craig Venter, Ph.D. Credit: J. Craig Venter Institute. Download High Resolution JPEG
Clyde A. Hutchison III, Ph.D. Credit: J. Craig Venter Institute. Download: High Resolution JPEG
John Glass, Ph.D. Credit: J. Craig Venter Institute. Download: High Resolution JPEG
Dan Gibson, Ph.D. Credit: J. Craig Venter Institute. Download: High Resolution JPEG
Ray-Yuan Chuang, Ph.D. Credit: J. Craig Venter Institute. Download: High Resolution JPEG
Electron micrographs of clusters of JCVI-syn3.0 cells magnified about 15,000 times. This is the world’s first minimal bacterial cell. Its synthetic genome contains only 473 genes. Surprisingly, the functions of 149 of those genes are unknown. Credit: Tom Deerinck and Mark Ellisman of the National Center for Imaging and Microscopy Research at the University of California at San Diego Download: High Resolution JPEG
Download: High Resolution JPEG
Download: High Resolution JPEG
Four design-build-test cycles produced JCVI-syn3.0. (A) The cycle for genome design, building by means of synthesis and cloning in yeast, and testing for viability by means of genome transplantation. After each cycle, gene essentiality is reevaluated by global transposon mutagenesis. (B) Comparison of JCVI-syn1.0 (outer blue circle) with JCVI-syn3.0 (inner red circle), showing the division of each into eight segments.The red bars inside the outer circle indicate regions that are retained in JCVI-syn3.0. (C) A clusterof JCVI-syn3.0 cells, showing spherical structures of varying sizes (scale bar, 200 nm). Credit: J. Craig Venter Institute. Download: High Resolution PDF
Fig. 7. Comparison of syn1.0 and syn3.0 growth features. (A) Cells derived from 0.2 µm–filtered liquid cultures were diluted and plated on agar medium to compare colony size and morphology after 96 hours (scale bars, 1.0 mm). (B) Growth rates in liquid static culture were determined using a fluorescent measure (relative fluorescent units, RFU) of double-stranded DNA accumulation over time (minutes) to calculate doubling times (td). Coefficients of determination (R2) are shown. (C) Native cell morphology in liquid culture was imaged in wet mount preparations by means of differential interference contrast microscopy (scale bars, 10 µm). Arrowheads indicate assorted forms of segmented filaments (white) or large vesicles (black). (D) Scanning electron microscopy of syn1.0 and syn3.0 (scale bars, 1 µm). The picture on the right shows a variety of the structures observed in syn3.0 cultures. Credit: J. Craig Venter Institute. Download: High Resolution PDF

ORIGINAL: J Craig Venter Institute

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