Steven Sandler

Professor

Phone: 413-577-4391
Fax: 413-545-1578
Email: sandler@microbio.umass.edu
Mailing address

Ph.D.: Department of Molecular Biology, University of California, Berkeley, 1984

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Lab Rotation Projects

DNA Replication, Recombination and Cell Division in E. coli

Our laboratory is interested in the processes of DNA replication, Recombination and Cell Division in E. coli. In particular, we are interested in how these processes are coordinated. It has been recently shown that replication forks stop for a variety of mundane, housekeeping reasons as they replicate chromosomes. This happens both in prokaryotic and eukaryotic cells. After stopping, these forks need to get repaired. This is thought to occur predominately by homologous recombination. Then after repair, these forks need to get up and running again. A special set of proteins call the Replication Restart Proteins form a multi-subunit complex at a repaired replication fork that helps to reload the replisome. In E. coli, the Replication Restart Proteins include PriA, PriB, PriC, DnaT, DnaC, and DnaB.

A model for thinking about the multiple pathways for replication restart. The dark and light lines indicate major and minor pathways respectively. The dotted lines represent an alternate pathway available in the presence of a suppressor.

Our approach is a combination of genetics, molecular biology, cell biology and genomics. We used the power of genetics to look for connections between replication and recombination. We use molecular biology to engineer the chromosome both physically and genetically to test models for how replication forks collapse and get restarted. We use the Green and Red Fluorescent Proteins to monitor where in the cell do these processes occur and to measure gene expression in individual cells.

Left: priA mutant cells that have the sulA-gfp reporter gene. SOS expression in these cells is not uniform.

Right: localization of RecA-rfp (red fluorescent protein) in E. coli cells.

Other areas of interest and study include the genetics of iron reduction in Geobacter sulfurreducens.

Selected Publications

Marielle C. Gruenig, Nicholas Renzette, Edward Long, Sindhu Chitteni-Pattu, Ross B. Inman, Michael M. Cox and Steven J. Sandler (2008) RecA-mediated SOS induction requires an extended filament conformation but no ATP hydrolysis. Molecular Microbiology 69(5) : 1165-1179

Richard Centore, Roxane Lestini and Steven J. Sandler (2007) XthA (Exonuclease III) regulates loading of RecA onto DNA substrates in log phase Escherichia coli cells. Molecular Microbiology 67(1) : 88-101.

Matthew Lopper, Ruethairat Boonsombat, Steven J. Sandler and James L. Keck (2007) A hand-off mechanism for primosome assembly in replication restart. Molecular Cell 26 : 781-793.

Richard Centore and Steven J. Sandler (2007) UvrD limits the number and intensities of RecA-GFP structures in Escherichia coli K-12. Journal of Bacteriology 189(7): 2915-2920.

Ruethairat Boonsombat, Su-Ping Yeh, Amy Milne and Steven J. Sandler (2006) A novel dnaC mutation that suppresses priB rep mutant phenotypes in Escherichia coli K-12. Molecular Microbiology 60(4): 973-983.

Renzette, Nicholas, Nathan Gumlaw, Jared T. Nordman,  Marlee Krieger,  Su-Ping Yeh,  Edward Long, Richard Centore, Ruethairat Boonsombat and Steven J. Sandler (2005) Localization of RecA in E. coli K-12 Using RecA-GFP. Molecular Microbiology 57(4): 1074-1085.

Sandler, Steven J. (2005) Requirements for Replication Restart Proteins during Constitutive Stable DNA Replication (cSDR) in E. coli K-12. Genetics 169(4) : 1799-1806.

Hinds, Tania and Steven J. Sandler (2004) Allele specific synthetic lethality between priC and dnaA ts alleles at the permissive temperature of 30C in E. coli K-12. BMC Microbiology 4: 47-58.

McCool, Jesse D., Edward Long, Joseph F. Petrosino, Hilary A. Sandler, Susan M. Rosenberg and Steven J. Sandler (2004) Measurement of SOS expression in individual Escherichia coli K-12 cells using fluorescence microscopy. Molecular Microbiology 53:1343-1357.

McCool, Jesse D., Christopher C. Ford and Steven J. Sandler (2004) A dnaT mutant with similar phenotype to a priA2::kan mutant in Escherichia coli K-12. Genetics 167:569-578.

Lloyd, Jonathan R., C. Leang, A. L. Hodges Myerson, M. V. Coppi, S. Cuifo, B. Methe, S. J. Sandler, D. R. Lovley (2002) Biochemical and genetic characterization of CycP, a periplasmic C-type cytochrome in Geobacter sulfurreducens. Biochemical Journal 369: 153-61.

McCool, Jesse D. and Steven J. Sandler (2001) Effects of mutations involving cell division, recombination, and chromosome dimer resolution on a priA2::kan mutant. Proceedings of the National Academy of Science, USA 98(15): 8203-8210.

Sandler, Steven J., Jesse D. McCool, Tu Thein Do and Runa Ulsoe Johansen (2001) PriA mutations that affect PriA-PriC function during replication restart. Molecular Microbiology 41: 697-704.

Coppi, Maddalena V., Ching Leang, Steven J. Sandler and Derek R. Lovley (2001) Development of a Genetic System for Geobacter sulfurreducens. Applied and Environmental Microbiology 67(7):3180-3187.

Cox, M. M., M. F. Goodman, K. N. Kreuzer, D. J. Sherratt, S. J. Sandler, Kenneth J. Marians (2000) Re-establishment of Inactivated Replication Forks as Bacterial Housekeeping Function. Nature 404:37-41.

Sandler, Steven J. and Kenneth J. Marians (2000) Role of PriA in Replication Fork Reactivation in Escherichia coli. Journal of Bacteriology 182(1): 9-13.

Sandler, Steven J. (2000) Multiple Genetic Pathways for Restarting DNA Replication Forks in E. coli K-12. Genetics 155(2): 487-497.

Liu, Joing, Liewei Xu, Steven J. Sandler and Kenneth J. Marians (1999) Replication fork assembly at recombination intermediates is required for bacterial growth. PNAS 96(7): 3552-3555.

Sandler, Steven J. Phillip Hugenholtz, Christa Schleper, Edward F. DeLong, Norman R. Pace and Alvin J. Clark (1999) Diversity of radA genes from cultured and uncultured Archaea: Comparative analysis of their putative RadA proteins and their use as a phylogenetic marker. Journal of Bacteriology 181(3): 907-915.

Sandler, Steven J. Kenneth J. Marians, Kenton H. Zavitz, Jaime Coutu, Michelle A. Parent and Alvin J. Clark (1999) DnaC mutations suppress defects in DNA replication and recombination associated functions in priB and priC double mutants in E. coli K-12. Molecular Microbiology. (final revision).

Kim, Rosalind, Steven J. Sandler, Stanley Goldman, Hisao Yokota, Alvin J. Clark, and Sung-Hou Kim (1998) Overexpression of archaeal proteins in Escherichia coli. Biotechnology Letters 20(3):207-210.

Seitz, Erica, Joel P. Brockman, Steven J. Sandler, A. John Clark, and Stephen C. Kowalczykowski (1998) RadA protein, an archaeal RecA protein homologue, catalyzes DNA strand exchange. Genes and Development 12(9) :1248-1253.

Brendel, Volker, Luciano Brocchieri, Steven J. Sandler, Alvin J. Clark, and Samuel Karlin (1997) Evolutionary comparisons of RecA-like proteins across all major kingdoms of living organisms. Journal of Molecular Evolution 44: 528-541.

Sandler, Steven J., Leslie H. Satin, Hardeep Sarma and Alvin J. Clark (1996) recA-like genes from three archaean species with putative protein products similar to Rad51 and Dmc1 proteins of the yeast Saccharomyces cerevisiae. Nucleic Acids Research 24 (11): 2125-2133.

Sandler, Steven J., Hardeep S. Sarma and Alvin J. Clark (1996) Differential suppression of priA2::kan phenotypes in E. coli K-12 by mutations in priA, lexA, and dnaC. Genetics 143 (1): 5-13.

Sandler, Steven J. (1996) DnaC809 distinguishes between overlapping functions for recF and priA in cell viability and UV-inducible SOS expression in E. coli K-12. Molecular Microbiology 19 (4): 871-880.

Hegde, Srikanth, Steven J. Sandler, Alvin J. Clark and Murty V. V. S. Madiraju (1995) Evidence that recO and recR mutations delay SOS induction in Escherichia coli K-12. Molecular and General Genetics 246: 254-258.

Sandler, Steven J. (1994) Studies on the mechanism of reduction of UV-inducible sulAp expression by recF overexpression in E. coli K-12. Molecular and General Genetics 245: 741-749.

Clark, Alvin J. and Steven J. Sandler (1994) Homologous genetic recombination: The pieces begin to fall into place. Critical Reviews in Microbiology 20(2):125-142.

Sandler, Steven J. and Alvin J. Clark (1994) Mutational analysis of sequences in the recF gene of E. coli K-12 that affect the level of translation. Journal of Bacteriology 176: 4011-4016.

Sandler, Steven J. and Alvin J. Clark (1994) RecOR suppression of mutant recF phenotypes in E. coli K-12. Journal of Bacteriology 176: 3661-3674.

Clark, Alvin J., Vineet Sharma, Stephen Brenowitz, Charles C. Chu, Steven Sandler, Leslie Satin, Ann Templin, Irit Berger, and Amikam Cohen (1993) Genetic and molecular analysis of the C-terminal region of the recE gene from the Rac prophage of E. coli K-12. Journal of Bacteriology 175: 7623-7682.

Sandler, Steven J. and Alvin J. Clark (1993) Use of high and low level overexpression plasmids to test mutant alleles of the recF Gene of E. coli K-12 for partial activity. Genetics 135: 643-654.

Sandler, Steven J., Bryce Chackerian, John T. Li and Alvin J. Clark (1992) Sequence and complementation analysis of recF genes from Escherichia coli K-12, Salmonella typhimurium, Pseudomonas putida and Bacillus subtilis: Evidence for a phosphate binding loop. Nucleic Acids Research 20: 839-845.

Sandler, Steven J. and Alvin J. Clark (1990) Factors affecting expression of the recF gene of E. coli K-12. Gene 86: 35-43

Department of Microbiology
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