Texas A&M Health Science Center, College Station, TX

• Regents Professor, Texas A&M Health Science Center, 12/08 to present
• Distinguished Professor of Molecular and Cellular Medicine, 3/04 to present
• E.L. Wehner-Welch Foundation Chair in Chemistry, 9/94 to present
• Professor of Medical Biochemistry & Genetics, 9/94 to 3/04
• Director, Molecular Biophysics Training Program, 2/00 to 3/05; member, 2/05 to 6/08
• Mechanistic Studies at the Host-Pathogen Interface Training Program, 7/03 to present

Texas A&M University, College Station, TX

• Distinguished Professor of Chemistry, 9/02 to present
• Professor of Biochemistry and Biophysics, 9/95 to present
• Professor of Chemistry, 9/94 to 8/02
• Chemistry-Biology Interface Training Program, 9/95 to 5/02
• Center for Advanced Biomolecular Research, 4/00 to 5/06

tRNA Probes, LLC

• Founder and CEO, 1/09 to present

Synergen, Inc., Boulder, CO

• Consultant, 11/92 to 2/95

Promega Corporation, Madison, WI

• Consultant, 8/91 to 11/97

University of Oklahoma, Norman, OK

• Grayce B. Kerr Centennial Chair, Department of Chemistry and Biochemistry, 4/92 to 8/94
• Professor, Department of Chemistry and Biochemistry, 9/87 to 8/94
• Associate Professor, Department of Chemistry, 9/83 to 8/87
• Assistant Professor, Department of Chemistry, 9/77 to 8/83

University of Oklahoma Health Sciences Center, Oklahoma City, OK

• Adjunct Professor, Department of Biochemistry and Molecular Biology, 9/87 to 8/94
• Adjunct Associate Professor, Department of Biochemistry and Molecular Biology, 9/83 to 8/87

University of California at San Francisco, San Francisco, CA

• Visiting Professor, Department of Biochemistry and Biophysics, 8/84 to 12/84

Columbia University, New York, NY

• Helen Hay Whitney Postdoctoral Research Associate, Department of Chemistry, 12/73 to 6/77. Laboratory of Charles R. Cantor

Milton Academy, Milton, MA

• Teacher (Physics, Chemistry, Advanced Physics, General Science), academic years 1964 to 65, 1968 to 69
• Head Coach (1967 to 69) and assistant coach (1964 to 67), varsity football; assistant coach, varsity basketball

Educational Enrichment Program, Milton, MA

• Teacher (Science/Experimental Psychology) 6/68 to 8/68

Phillips Andover Academy, Andover, MA

• Teacher (Physics/Chemistry), 6/67 to 8/67