Academic Research Experience

Timothy P. Spann, Ph. D

Dr. Spann has extensive research experience in a variety of areas in cell biology, with particular focus on cell cycle regulation, cell differentiation and the role that nuclear organization plays in DNA replication and gene regulation.

Dr. Spann’s graduate research was in the laboratory of Dr. John Newport at the University of California, San Diego. There he examined the mechanisms of nuclear disassembly during mitosis using cell free mitotic and interphase extracts prepared from Xenopus laevis eggs. Dr. Spann also investigated the molecular basis of chromatin organization in the nucleus.

As a HHMI Associate, Dr. Spann’s postdoctoral research was carried out in the laboratory of Dr. Richard Gomer at Rice University. In order to identify genes involvedin the cell fate decision process of Dictyostelium, i.e., differentiating into either prespore or prestalk cells, Dr. Spann develop a novel shotgun antisense mutagenesis technique. The method involved constructing a library of genes, each cloned in an antisense orientation to repress the transcript of the complementary gene when transfected into cells. Transfection of a large number of cells with the antisense library allowed screening the effect of inhibiting thousands of genes and led to the identification of 26 novel genes involved in the cell fate decision pathway. A further advantage of the method is that with PCR the antisense transcript is readily isolated, identified and the effect confirmed.

At Northwestern University, initially as a postdoctoral fellow and subsequently as an Assistant Research Professor in the laboratory of Dr. Robert Goldman, Dr. Spann’s research addressed the role nuclear organization plays in the replication of DNA and gene transcription. Using normal and dominant negative mutant forms of nuclear lamins in mammalian cells and cell free extracts prepared from both Xenopus eggs and embryos, Dr. Spann analyzed the effects of altering the organization of nuclear lamins. Nuclear lamins are structural proteins of the nucleus and have been linked to a variety of human diseases such as progeria, Emery-Dreifuss muscular dystrophy, diabetes, and dilated cardiomyopathy. He found that disruption of nuclear lamin organization specifically blocked the elongation phase of replication and altered the organization of elongation factors DNA synthesis. Disruption of nuclear lamin organization also blocks the transcription of RNA polymerase II dependent genes and causes an alteration in the distribution of the TATA binding protein, while transcription of polymerase I and III dependent genes continues.

Among the technologies utilized in these projects were cloning, construction of protein expression vectors, library construction, antisense inhibition, cell fractionation, protein expressions systems, protein purification, protein and nucleic acid detection techniques, protein nucleic acid interaction assays such as foot-printing and filter binding assays, antibody production and purification, the production and manipulation of functional cell free extracts, microinjection of mammalian single cell and Xenopus embryos, fluorescence microscopy including immunofluorescence and live cell observations with GFP-labeled proteins.


Back to Profile	Academic Research Experience Timothy P. Spann, Ph. D Dr. Spann has extensive research experience in a variety of areas in cell biology, with particular focus on cell cycle regulation, cell differentiation and the role that nuclear organization plays in DNA replication and gene regulation. Dr. Spann’s graduate research was in the laboratory of Dr. John Newport at the University of California, San Diego. There he examined the mechanisms of nuclear disassembly during mitosis using cell free mitotic and interphase extracts prepared from Xenopus laevis eggs. Dr. Spann also investigated the molecular basis of chromatin organization in the nucleus. As a HHMI Associate, Dr. Spann’s postdoctoral research was carried out in the laboratory of Dr. Richard Gomer at Rice University. In order to identify genes involvedin the cell fate decision process of Dictyostelium, i.e., differentiating into either prespore or prestalk cells, Dr. Spann develop a novel shotgun antisense mutagenesis technique. The method involved constructing a library of genes, each cloned in an antisense orientation to repress the transcript of the complementary gene when transfected into cells. Transfection of a large number of cells with the antisense library allowed screening the effect of inhibiting thousands of genes and led to the identification of 26 novel genes involved in the cell fate decision pathway. A further advantage of the method is that with PCR the antisense transcript is readily isolated, identified and the effect confirmed. At Northwestern University, initially as a postdoctoral fellow and subsequently as an Assistant Research Professor in the laboratory of Dr. Robert Goldman, Dr. Spann’s research addressed the role nuclear organization plays in the replication of DNA and gene transcription. Using normal and dominant negative mutant forms of nuclear lamins in mammalian cells and cell free extracts prepared from both Xenopus eggs and embryos, Dr. Spann analyzed the effects of altering the organization of nuclear lamins. Nuclear lamins are structural proteins of the nucleus and have been linked to a variety of human diseases such as progeria, Emery-Dreifuss muscular dystrophy, diabetes, and dilated cardiomyopathy. He found that disruption of nuclear lamin organization specifically blocked the elongation phase of replication and altered the organization of elongation factors DNA synthesis. Disruption of nuclear lamin organization also blocks the transcription of RNA polymerase II dependent genes and causes an alteration in the distribution of the TATA binding protein, while transcription of polymerase I and III dependent genes continues. Among the technologies utilized in these projects were cloning, construction of protein expression vectors, library construction, antisense inhibition, cell fractionation, protein expressions systems, protein purification, protein and nucleic acid detection techniques, protein nucleic acid interaction assays such as foot-printing and filter binding assays, antibody production and purification, the production and manipulation of functional cell free extracts, microinjection of mammalian single cell and Xenopus embryos, fluorescence microscopy including immunofluorescence and live cell observations with GFP-labeled proteins.