UCONN

HEALTH

Photo of Lawrence A. Klobutcher, Ph.D.

Lawrence A. Klobutcher, Ph.D.

Professor, Department of Molecular Biology and Biophysics
Academic Office Location:
Molecular Biology and Biophysics
UConn Health
263 Farmington Avenue
Farmington, CT 06030-3305
Phone: 860-679-2816
Fax: 860-679-3408
Email: klobutcher@nso2.uchc.edu
Website(s):

Molecular Biology & Biochemistry Graduate Program

Education
DegreeInstitutionMajor
B.S.Loyola UniversityBiology
M.Phil.Yale UniversityHuman Genetics
Ph.D.Yale University Human Genetics

Post-Graduate Training
TrainingInstitutionSpecialty
PostdoctoralUniversity of ColoradoGenetic organization of hypotrichous ciliated protozoa in the laboratory of Dr. D. M. Prescott

Awards
Name of Award/HonorAwarding Organization
Who’s Who in AmericaWho's Who Amoung Students in Amerian Universities
“Superior” ratingMedical School Teaching Assessment Program
Postdoctoral Fellowship (declined). Anna Fuller Fund
National Institutes of Health Postdoctoral Fellowship, 1980-83. NIH
Hudson Award for summer study Loyola University
Member 1973-1974Blue Key National Honor Fraternity
Biology Medal Loyola University
Illinois State Scholar, 1970-1974. Illinois Student Assistance Commission
Name & DescriptionCategoryRoleTypeScopeStart YearEnd Year
Farmington Public Schools FoundationAdvisory CommitteeBoard of DirectorsExternalLocal2010
Student Evaluation and Appeal Review Committee (SEARC; Medical & Dental students)Advisory CommitteeMemberOtherUniversity2009
LCME Institutional Setting Self-Study CommitteeAdvisory CommitteeCo-ChairUConn HealthUniversity20082010
Education CouncilEducation CommitteeMemberUConn HealthUniversity20072011
Executive Committee of the Graduate Faculty CouncilAdvisory CommitteeMemberUConn HealthUniversity20072011
Eukaryotic CellEditorial BoardBoard of ReviewersExternalNational2006
Medical School Oversight CommitteeEducation CommitteeVice ChairUConn HealthUniversity20062007
Education Council Subcommittee on Evaluation of TeachingEducation CommitteeMemberUConn HealthUniversity2006
Nominating Committee, International Society of ProtistologistsProfessional/Scientific OrganizationMemberExternalNational20062007
The American Society for Cell BiologyProfessional/Scientific OrganizationMemberExternalNational2005
American Society for MicrobiologyProfessional/Scientific OrganizationMemberExternalNational2005
American Society for Cell BiologyProfessional/Scientific OrganizationMemberExternalNational2005
Medical Council Subcommittee on Tenure and SalaryAdvisory CommitteeCo-ChairUConn HealthUniversity20042005
Graduate Programs Strategic Planning CommitteeEducation CommitteeMemberUConn HealthUniversity20042005
FASEB Summer Research Conference on “Ciliate Molecular Biology” Professional/Scientific OrganizationCo-ChairExternalNational2003
Board of Scientific Advisors, joint NIGMS/NSF-funded Tetrahymena Genome-Sequencing ProjectAdvisory CommitteeMemberExternalNational20032006
Medical Council Subcommittee on Post-Tenure ReviewAdvisory CommitteeMemberUConn HealthUniversity2003
Medical School Council, Executive CommitteeEducation CommitteeMemberUConn HealthUniversity20032005
Tetrahymena Genome Sequencing Steering Committee Advisory CommitteeSteering CommitteeExternalNational20012007
Journal of Eukaryotic MicrobiologyEditorial BoardAssociate EditorExternalNational20002008
UCONN Medical School Senior Appointments and Promotions Committee Advisory CommitteeMemberUConn HealthUniversity20002007
Curriculum Committee, Graduate Program in Molecular Biology and BiochemistryEducation CommitteeChairUConn HealthUniversity19992000
Medical School Council Education CommitteeMemberUConn HealthUniversity19972005
Journal of Protozoology/Journal of Eukaryotic MicrobiologyEditorial BoardReviewerExternalNational19972000
Medical Council Nominating CommitteeAdvisory CommitteeChairmanUConn HealthUniversity1995
U. Conn. Health Center Graduate Programs CommitteeAdvisory CommitteeVice ChairUConn HealthUniversity19951996
UCONN Graduate School task force on Area Review CommitteesAdvisory CommitteeMemberUConn HealthUniversity19951996
Advisory Panel for Eukaryotic Genetics, National Science Foundation, 1993-96, 2001. Advisory CommitteePanel memberExternalNational1993
Graduate Faculty Council and Executive CommitteeAdvisory CommitteeMemberUConn HealthUniversity19931995
Board of Reviewers,97-00. Advisory CommitteeMemberExternalNational19921995
University of Connecticut Health Center Graduate Programs CommitteeEducation CommitteeChairmanUConn HealthUniversity19921995
Univ. of Conn. Health Center Strategic Planning/Research Focus CommitteeResearch CommitteeMemberUConn HealthUniversity1992
Dental School Council, 1984-89Advisory CommitteeMemberUConn HealthUniversity19911993
Univ. of Conn. Health Center Oversight Committee on Research (OCOR)Research CommitteeMemberUConn HealthUniversity19911993
Dental School CouncilEducation CommitteeMemberUConn HealthUniversity19911993
Friends of Farmington EducationProfessional/Scientific OrganizationMemberExternalLocal19901991
Gordon Conference on "The Molecular Biology of Ciliated Protozoa"Professional/Scientific OrganizationCo-ChairExternalNational1989
Graduate Program in Molecular Biology and BiochemistryEducation CommitteeDirectorUConn HealthUniversity19891992
Graduate Programs’ “Undergraduate Symposia on Current Topics in the Biological and Biomedical SciencesOtherCo- ChairUConn HealthUniversity1989
Journal of Protozoology/Journal of Eukaryotic MicrobiologyEditorial BoardReviewerExternalNational19891995
Committee on Research Safety & Environmental HealthAdvisory CommitteeVice ChairUConn HealthUniversity19881989
University of Connecticut Research Foundation Institutional Grant Review, Basic SciencesAdvisory CommitteeMemberUConn HealthUniversity19871990
Graduate Program in Molecular Biology and BiochemistryEducation CommitteeAssistant DirectorUConn HealthUniversity19871989
Graduate Programs’ “Undergraduate Symposia on Current Topics in the Biological and Biomedical SciencesOtherChairmanUConn HealthUniversity1987
Society of Protozoologists Professional/Scientific OrganizationMemberExternalNational1986
Admissions Committee, Graduate Program in Molecular Biology and BiochemistryAdvisory CommitteeMemberUConn HealthUniversity19861995
Curriculum Revision Committee, Graduate Program in Molecular Biology and BiochemistryEducation CommitteeMemberUConn HealthUniversity19851986
American Cancer Society Institutional Grant Review CommitteeStudy SectionGrant ReviewerUConn HealthUniversity19841987
Medical School Applicant InterviewsAdvisory CommitteeMemberUConn HealthUniversity19841986
Dental School CouncilEducation CommitteeMemberUConn HealthUniversity19841989
Sigma Xi, Scientific Research SocietyProfessional/Scientific OrganizationMemberExternalNational1980
American Association for the Advancement of ScienceProfessional/Scientific OrganizationMemberExternalNational1978
The laboratory employs ciliated protozoa as model organisms to study basic cellular processes. Currently, the following two areas of research are being pursued:

Phagocytosis in Tetrahymena thermophila.
Phagocytosis refers to the process by which cells are able to ingest large particles (>1 um). In vertebrates, phagocytosis mainly occurs in specialized cells of the immune system (macrophages, monocyctes, and neutrophils). Such “professional phagocytes” serve as a primary line of defense by ingesting invading pathogens, and also activate specific immune responses. In addition, phagocytosis is important in clearing cell debris and for tissue remodeling during development. Finally, a number of microbial pathogens (e.g., Salmonella, Legionella, Mycobacterium, anthrax, and specific types of yeast) utilize and/or subvert phagocytosis as a means of entering cells. Learning how phagocytosis is carried out is thus important for understanding tissue maintenance and immune defense in humans, as well as the infection strategies of some disease-causing microorganisms.

Research in a number of experimental systems has made it clear that phagocytosis is a multistep process that involves hundreds of genes and proteins. Nonetheless, the identities and functions of phagocytic genes, and the molecular mechanisms of phagocytosis, are still poorly understood. We are seeking to further our understanding of phagocytosis by studying Tetrahymena thermophila, an organisms particularly amenable to genetic and molecular biological analysis. In nature, Tetrahymena uses phagocytosis to feed on bacteria and other microorganisms, but in the laboratory it can be grown on defined culture medium where phagocytosis is not an essential process. This feature has allowed us to develop a screening procedure for isolating cells that are deficient in phagocytosis, which will lead to the identification of new genes/proteins that are involved in various steps of the process. In addition, a system for the efficient purification of phagosomes from Tetrahymena has been developed, and we are pursuing mass spectrometry approaches to define the complete Tetrahymena phagosome proteome. This analysis is expected to identify numerous new genes previously unsuspected of playing a role in phagocytosis. The genetic tools available in Tetrahymena, coupled with its favorable cytological features, will allow us to investigate the localization and function of these novel proteins.

Frequent Frameshifting in Euplotes crassus.
Ciliated protozoa, including members of the genus Euplotes, are unusual in that they employ alternative genetic codes to specify how mRNAs are translated into proteins. Previously. the genetic code had been considered universal and unalterable. The observation that many ciliates have altered genetic codes in which canonical stop codons are decoded as sense (stop codon reassignment) shows that even the code is subject to evolutionary pressure to change. In addition, recent data suggest that Euplotes genes also have an unusually high frequency of programmed +1 translational frameshifting. In our own pilot sequencing survey of 25 randomly selected genes, we observed 3 genes that require a +1 frameshift, indicating that more than 10% of the genes in the genome may require such a frameshift for expression. we have also carried out a phylogenetic analysis on the origin of frameshift sites within the telomerase reverse transcriptase genes of Euplotes species, and have found that two frameshift sites have arisen during the evolution of this group. In other organisms, frameshifting is involved in regulation of gene expression. The apparent high frequency of frameshift genes in Euplotes is unprecedented, and suggests that the organism has particular features that have potentiated the origin of frameshift sites within genes and that allow for efficient frameshifting.

The mechanism of frameshifting in Euplotes is unknown. The initial open reading frame of all the Euplotes frameshift genes terminates with an AAA lysine codon, followed by a stop codon (usually UAA), and an additional A residue. This AAA-UAA-A motif suggests that the Euplotes genes may employ a "shifty stop" mode of frameshifting. There are two features of a typical "shifty stop" site. First, there is a slippery codon (AAA in Euplotes) that, during translation, would allow the cognate tRNA to slip forward 1 base and still maintain two correct base pairs with the mRNA. Second, there is a poorly recognized termination tetranucleotide (the stop codon plus the next base) that is thought to slow translation, providing an opportunity for the usually rare slippage in reading frame. Surprisingly, and perhaps contrary to this model, UAA-A frequently occurs at natural sites of translation termination in Euplotes. To explain this apparent enigma, we have developed a model in which stop codon reassignment is linked to the mechanism of frameshifting (Klobutcher and Farabaugh, 2002, Cell 111:763). Stop codon reassignment requires changes in the translation termination factor eRF1 such that it can no longer recognize the reassigned stop codon (UGA in Euplotes). We postulate that these changes have also impaired the recognition of the remaining stop codons, so that translation termination is a slow step. Thus, the slowing of translation when a stop codon is encountered would provide an opportunity for a +1 frameshift in the context of a slippery codon. We plan to test this model by both defining the minimal nucleic acid sequence element(s) that promotes frameshifting, and by determining if Euplotes eRF1 has reduced affinity for stop codons. As a further test of the hypothesis, we plan to determine if a high frequency of frameshifting is observed in other ciliates that have independently undergone stop codon reassignment.

Not accepting students for Lab Rotations at this time

Journal Articles

Book Chapters

  • “Macronucleus”, “Micronucleus”, and “Macronuclear Development, in Ciliates”.
    Klobutcher, L.A. Encyclopedia of Genetics. 2001 Jan;1133-1136 and 1204
  • The special case of the hypotrichs
    Klobutcher, L.A. and Prescott, D.M. The Molecular Biology of Ciliated Protozoa 1986 Jan;
  • Eucaryotic Gene Regulation
    Scangos, G., Klobutcher, L., and Ruddle, F.H. Gene amplification as a concomitant to chromosome mediated gene transfer. 1979 Jan;445-456

Abstracts

  • Comparative genomics of Euplotes: insights into genome organization, genetic code and frameshifting.
    Alexei V. Lobanov, Christina Miceli, Anton A. Turanov, Lawrence A. Klobutcher, Pavel V. Baranov, Dolph L. Hatfield, and Vadim N. Gladyshev. FASEB Conference on “Ciliate Molecular Biology”, Orthodox Academy of Crete, Greece. 2011 Jan;
  • The Euplotes crassus genome: selenoproteome and position-specific insertion of selenocysteine.
    Alexei V. Lobanov, Anton A. Turanov, Lawrence A. Klobutcher, Dolph L. Hatfield, and Vadim N. Gladyshev. Selenium 2010 Conference 2010 Jan;

Other

Reviews

Short Surveys