Profile Photo of Tom McKnight
Tom McKnight

Department Head

Fax: 979-845-2891

3258 TAMU
Biological Sciences Building East
Room 202C
Butler Hall
Room 100B

Biological Sciences Building East
Room 206

Joined the Department in 1985

  • B.S., 1975, University of Georgia, Microbiology.
  • Ph.D., 1983, University of Georgia, Molecular and population genetics.
  • Postdoctoral research: Atlantic Richfield Plant Cell Research Institute


Faculty of Genetics
Faculty of Molecular and Environmental Plant Sciences

Graduate Program in Molecular Cell Biology

Plant Molecular and Cell Biology

My lab is currently investigating mechanisms that regulate telomerase activity in plants. We previously showed that the pattern of telomerase expression in plants is remarkably similar to the pattern seen in humans, despite fundamental differences in development between plants and animals. Telomerase is abundantly expressed in reproductive organs but is undetectable in most vegetative organs (Fitzgerald et al., 1996). Additionally, telomerase can be induced in leaves and other vegetative organs by exposure to exogenous auxin.

To isolate genes that regulate telomerase, we screened a large population of activation tagged lines of Arabidopsis thaliana, and found that several lines that ectopically express telomerase in leaves. The first line we characterized over-expressed a gene encoding a small zinc finger transcription factor we designated TELOMERASE ACTIVATOR 1 (Ren et al., 2004). This factor does not bind to the promoter for TERT, which encodes the catalytically active subunit of telomerase. Instead, it binds to and activates transcription of BT2, a gene encoding a component of a ubiquitin ligase (Ren et al., 2007). Our working model is that the BT2 ubiquitin ligase marks a telomerase repressor for destruction, thereby allowing expression of telomerase. Efforts in the lab are currently focused on identifying the presumed telomerase repressor protein and other proteins that interact with BT2.