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Department of Biochemistry and Molecular Biology

Houston, Texas

Images from biochemistry and molecular biology research
Verna and Marrs McLean Department of Biochemistry and Molecular Biology
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Shelley Sazer, Ph.D.

Shelley Sazer, Ph.D.

Associate Professor
Department of Biochemistry and Molecular Biology
Department of Molecular and Cellular Biology

ssazer@bcm.edu

Education and Awards

  • Ph.D., Biological Sciences, 1988, Stanford University
  • Postdoctoral, Microbiology/Biochemistry, 1988-1991, University of Oxford
  • Fulford Junior Research Fellow, 1988-1990, Somerville College, Oxford
  • Jane Coffin Childs Fund for Medical Research Fellow, 1988-1991
  • Marc Dresden Excellence in Graduate Education Award, 1995, Baylor College of Medicine
  • The Barbara and Corbin J. Robertson Jr. Presidential Award for Excellence in Education, 2009

Research Interests

Mitosis to Interphase Transition

Our investigations into the mitosis to interphase transition, including chromosome conformation, spindle formation and morphological changes in the nuclear envelope, are based on our characterization of a temperature sensitive mutant, pim1-d1ts, which is defective in all of these processes. pim1 encodes a guanine nucleotide exchange factor for the small evolutionarily conserved GTPase spi1/Ran.We are identifying and characterizing the regulators and effectors of this GTPase in order to understand how it influences cell cycle progression. Because Ran influences nucleoytoplasmic transport and other cellular processes by changing the stability of import carrier/cargo complexes we are also using a variety of approaches to identify these cargo proteins.

Nuclear Division

Fission yeast undergo a closed mitosis in which the mitotic spindle forms and elongates within the nucleus, which remains intact during the entire cell cycle. During mitosis the nucleus undergoes a precise sequence of shape changes from round to oblong to peanut to dumbbell before resolving into two daughter nuclei. When the Ran GTPase system is mis-regulated the nuclear envelope breaks as cells enter mitosis. In order to better understand the physical properties of the nucleus in this abnormal situation and during normal division, we are collaborating with a group of physicists to develop a computational model to describe nuclear division and generate testable hypotheses about this process.

The Spindle Checkpoint

The spindle checkpoint is a regulatory network that monitors spindle integrity and the attachment of chromosomes to the spindle. In the presence of defects, the checkpoint system arrests cells at the metaphase to anaphase transition. We have identified two evolutionarily conserved components of this system in fission yeast, Mad2p and Mph1p. We are currently focusing on the identification of novel components of this pathway and the characterization of cells in which the checkpoint system is defective.currently characterizing 60 mutants that have the hallmark characteristics of new spindle checkpoint components.

Nuclear Division in Fission Yeast.

NUCLEAR DIVISION IN FISSION YEAST. (A) Normal nuclear geometric transformations in the cell cycle of fission yeast. In interphase the volume of the nucleus doubles. When mitosis begins, the duplicated SPBs (BLUE) are embedded in the nuclear envelope and as they assume positions on opposite sides of the nucleus(GREEN) nucleate the assembly of microtubules that form the mitotic spindle (RED). As the spindle elongates the initially spherical nucleus is deformed into oval, peanut, and dumbbell shapes before resolving into two spherical daughter nuclei. Cytokinesis then physically separates the nuclei into two individual cells that initiate another round of cell division. (B) Symmetric nuclear division in wild type cells expressing a GFP-tagged nuclear specific reporter protein. (C) Asymmetric nuclear division in pim1-d1 mutant cells expressing a GFP-tagged nuclear specific reporter protein.

View articles published by Dr. Sazer.

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