Jeff Tabor

Background

I recieved my B.A. studying Biology and Biochemistry from the University of Texas in 2001. I studied evolutionary biology in the lab of Jim Bull for two years during that time.

I am currently a Ph.D. candidate in molecular biology at the University of Texas, studying with Andy Ellington. My primary interests include the forward design and programming of novel cellular behaviors (synthetic biology) using genetic regulation strategies at both the canonical protein/DNA interaction level (e.g. controlling POPS; Endy, Nature, 2005) and at the level of riboregulation (e.g. copious natural RNA regulators, or artificially designed regulators such as Bayer and Smolke, Nature Biotechnology 2005).

I am also interested in the quantitative characteristics of natural mechanisms of gene regulation and expression. Uncontrollable fluctuations in gene expression in populations of genetically identical individuals can lead to quantifiably diverse (even opposite) phenotypes within that population. It is becoming more and more obvious that biology, being evolutionarily adept as it is, has taken advantage of the noise inherent in gene expression to encode complex population level behaviors using simple genetic level specifications. For example, the virus HIV encodes a genetic amplifier in its genome, wherein a protein product of a gene results in higher transcription levels of that gene. Upon infection of a host cell, the levels of that protein product usually tend about some mean. Uncontrollable fluctuations below that mean at some critical time point result in the HIV genomes in that invaded cell going lysogenic. Fluctuations above that mean at some critical time point result in the HIV genomes in that cell going lytic. There are fitness advantages to such a bifuracted reproductive strategy, and this virus has used noise as opposed to hard-wired genetic to encode this behavior. Clearly, noise can sometimes be detrimental to cellular survival, and in certain instances biology has evolved ways to insulate, buffer or engineer away noise in gene expression as well.

Research

Noise

My research is currently focused on elucidating sources of noise generation and mechanisms of noise insulation in gene expression (much more to come).

Synthetic Biology

I have led the efforts of a synthetic biology group here at UT over the last two years which has designed and built a "bacterial photography" system in which a community of E.coli act as a biological film capable of capturing and permanently recapitulating any light image. This work was enabled by the design of an incredible chimeric light responsive genetic element from the Voigt lab at UCSF. Basically, Anselm Levskaya and Chris Voigt rewired a phytochrome protein from Synechocystis which normally changes conformation in response to light and transduces this into a change in gene expression in that organism to control an osmo-responsive genetic regulatorary system in E.coli. In order to retain the functionality of the phytochrome protein, the metabolism of E.coli had to be re-engineered to produce a ringed organic compound, phycocyanobilin (PCB). This work had previously been done in the Lagarias lab at UC-Davis. The result is a synthetic genetic signal transduction cascade in E.coli that is strongly responsive to light in the 660nm (red) range. The applications of the fine spatial control in gene expression afforded by light approach boundless (much more to come).

I am also working on the evolution of simple ribo-circuits in E.coli such as RNA-mediated operational amplifiers (more to come).