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Dr. Andre Walther - Cedar Crest College. Allentown, PA, US

Dr. Andre Walther Dr. Andre Walther

Associate Professor, Department of Biological Sciences and Director of the Genetic Engineering Program | Cedar Crest College


Focused on using the model organism "Baker's Yeast" to understand the underlying causes of cancer and its function in beer production.





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Dr. Andre Walther is an Associate Professor of Biology at Cedar Crest College. He contributes to Introductory Biology labs, Cell and Molecular Biology lecture and lab, and upper level courses in the Genetic Engineering program including Mammalian Cell Culture and Microscopy lab, Advanced PCR techniques lab, and Advanced Recombinant techniques lecture. He also maintains an active research lab with undergraduates focused on understanding the role of Replication Protein A in cellular responses to DNA damage in budding yeast. He is also doing research in the role of yeast in beer production and in identifying novel fungi for use in biofuel production.

Industry Expertise (5)

Education/Learning Training and Development Research Biotechnology Renewables and Environmental

Areas of Expertise (9)

Molecular Biology Molecular Genetics Cell Culture Protein Purification Cell Biology Biotechnology Genetic Engineering DNA Repair DNA Replication

Education (2)

University of Iowa - Carver College of Medicine: Ph.D., Biochemistry 2000

University of Northern Iowa: B.A., Chemistry and Biology 1994

Affiliations (2)

  • Pennsylvania Academy of Science
  • American Society for Microbiology

Languages (1)

  • French

Articles (5)

The DNA Damage Response and Checkpoint Adaptation in Saccharomyces cerevisiae: Distinct Roles for the Replication Protein A2 (Rfa2) N-Terminus Genetics Society of America


In response to DNA damage, two general but fundamental processes occur in the cell: (1) a DNA lesion is recognized and repaired, and (2) concomitantly, the cell halts the cell cycle to provide a window of opportunity for repair to occur. An essential factor for a proper DNA-damage response is the heterotrimeric protein complex Replication Protein A (RPA). Of particular interest is hyperphosphorylation of the 32-kDa subunit, called RPA2, on its serine/threonine-rich amino (N) terminus following DNA damage in human cells. The unstructured N-terminus is often referred to as the phosphorylation domain and is conserved among eukaryotic RPA2 subunits, including Rfa2 in Saccharomyces cerevisiae. An aspartic acid/alanine-scanning and genetic interaction approach was utilized to delineate the importance of this domain in budding yeast. It was determined that the Rfa2 N-terminus is important for a proper DNA-damage response in yeast, although its phosphorylation is not required. Subregions of the Rfa2 N-terminus important for the DNA-damage response were also identified. Finally, an Rfa2 N-terminal hyperphosphorylation-mimetic mutant behaves similarly to another Rfa1 mutant (rfa1-t11) with respect to genetic interactions, DNA-damage sensitivity, and checkpoint adaptation. Our data indicate that post-translational modification of the Rfa2 N-terminus is not required for cells to deal with “repairable” DNA damage; however, post-translational modification of this domain might influence whether cells proceed into M-phase in the continued presence of unrepaired DNA lesions as a “last-resort” mechanism for cell survival.

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Eukaryotic Replication Fork eLS


In eukaryotic cells, DNA (deoxyribonucleic acid) synthesis occurs at specific sites that move through the genome called replication forks. Multiprotein complexes at these forks catalyse the synthesis of two new strands of DNA using parental strands as templates to produce two complete copies of the parental DNA. The eukaryotic replication fork machinery must deal with the chromatin and chromosome structure of eukaryotic genomes, be able to replicate DNA in the context of a complex cell cycle, and be able to deal with the constant threat of mutations that could arise due to replication of damaged DNA, all while trying to efficiently replicate the DNA with high fidelity. The resulting eukaryotic replication fork is a tightly controlled, yet incredibly efficient biological machine capable of synthesizing billions of base pairs of DNA in the span of hours.

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Inactivation of Ku-mediated end joining suppresses mec1Δ lethality by depleting the ribonucleotide reductase inhibitor Sml1 through a pathway controlled by Tel1 … Molecular and Cellular Biology


RAD53 and MEC1 are essential Saccharomyces cerevisiae genes required for the DNA replication and DNA damage checkpoint responses. Their lethality can be suppressed by increasing the intracellular pool of deoxynucleotide triphosphates...

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A novel assay for examining the molecular reactions at the eukaryotic replication fork: activities of replication protein A required during elongation Nucleic Acids Research


Studies to elucidate the reactions that occur at the eukaryotic replication fork have been limited by the model systems available. We have established a method for isolating and characterizing Simian Virus 40 (SV40) replication complexes...

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Replication protein A interactions with DNA. 1. Functions of the DNA-binding and zinc-finger domains of the 70-kDa subunit Biochemistry


Human replication protein A (RPA) is a multiple subunit single-stranded DNA-binding protein that is required for multiple processes in cellular DNA metabolism. This complex, composed of subunits of 70, 32, and 14 kDa, binds to single-stranded DNA (ssDNA) with high affinity and participates in multiple protein−protein interactions...

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