Environmental Factor, March 2010, National Institute of Environmental Health Sciences

NIEHS Welcomes Four New Principal Investigators

By Laura Hall
March 2010

At Harvard, Guang Hu developed new tools and methods for gene silencing and large-scale high-throughput functional RNAi screens in mammalian cells. (Photo courtesy of Steve McCaw)

Patricia Jensen is currently investigating how genetic and environmental perturbations during development alter the fates and functions of noradrenergic neurons. (Photo courtesy of Steve McCaw)

Raja Jothi comes to NIEHS from another NIH Institute, the National Heart, Lung, and Blood Institute, where he was a research fellow. Jothi had an earlier postdoctoral fellowship at the National Center for Biotechnology Information, part of the National Library of Medicine, NIH. (Photo courtesy of Steve McCaw)

One of R. Scott Williams' research interests is the mechanisms of DNA repair factor inactivation in heritable diseases. (Photo courtesy of
Steve McCaw)

NIEHS recently welcomed four new tenure track principal investigators in the Division of Intramural Research (DIR) - Guang Hu, Ph.D., Patricia Jensen, Ph.D., Raja Jothi, Ph.D., and R. Scott Williams, Ph.D. These outstanding young researchers have impressive expertise in stem cell research, bioinformatics, neuronal development, and structural biology.

Acting Scientific Director, John Pritchard, Ph.D., said NIEHS recruited these scientists to help the DIR program move into new areas of research. In conjunction with the DIR laboratory chiefs, Pritchard also put two other new positions on the division's priority list - environmental epidemiologist and developmental biologist - but said filling these two positions is unlikely this fiscal year.

Guang Hu - Stem Cell Biologist

Hu(http://www.niehs.nih.gov/research/atniehs/labs/lmc/stemcell/index.cfm), a principal investigator of the Stem Cell Biology Group in the Laboratory of Molecular Carcinogenesis (LMC)(http://www.niehs.nih.gov/research/atniehs/labs/lmc/index.cfm), studies stem cells. Unlike other cells, stem cells can renew themselves indefinitely and differentiate - change into numerous cell types. Hu studies the molecular basis of stem cell differentiation and self-renewal, screening for the genes involved and their effects on development.

"We were delighted to be able to recruit Dr. Guang Hu from Harvard to establish the stem cell biology group in the LMC last fall," said Trevor Archer, Ph.D., chief of the LMC. "Guang is a terrific young scientist who will bring exciting new expertise in genome-wide RNAi screens to the LMC and NIEHS. His studies will improve our knowledge about mammalian embryogenesis and may facilitate the development of stem cell therapies."

Patricia Jensen - Neurobiologist

Jensen (http://www.niehs.nih.gov/research/atniehs/labs/ln/dn/index.cfm) is the principal investigator of the Developmental Neurobiology Group in the Laboratory of Neurobiology (LN)(http://www.niehs.nih.gov/research/atniehs/labs/ln/index.cfm). She studies how genes and environmental factors affect neuronal development to help understand cognitive diseases like autism and Alzheimer's disease. Jensen uses genetic fate-mapping techniques in mice to visually track a specific brain neuronal subtype and define the molecular requirements for each step in its development.

"Environmental disruption of brain development produces lifelong costs in human cognitive potential and quality of life," explained Dave Armstrong, Ph.D., chief of the LN. "Dr. Jensen will use genetic techniques to identify functional subsets of neurons in the brain and then selectively disrupt their function. The resulting behavioral phenotypes should complement human imaging studies and provide new model systems for testing new pharmacological treatments for some of these disorders."

Raja Jothi - Biostatistician

Systems Biology Principal Investigator Jothi ( See Story on page 14 (http://www.nih.gov/catalyst/2009/09.05.01/catalyst_v17i3.pdf) ) is the newest member of the Biostatistics Branch (BB)(http://www.niehs.nih.gov/research/atniehs/labs/bb/index.cfm). Jothi uses computational and experimental methods to characterize gene regulatory elements - segments of DNA to which regulatory proteins (http://ghr.nlm.nih.gov/handbook/howgeneswork/geneonoff) bind preferentially to control gene expression - to understand the inherent patterns of gene expression and silencing as cells develop and differentiate.

"We are extremely pleased with the addition of Dr. Raja Jothi to our branch," said Clarice Weinberg, Ph.D., chief of the Biostatistics Branch. "Raja is an accomplished computational biologist, bringing to NIEHS a unique array of skills in biomathematics and wide-ranging interests in the dynamics and mechanisms of gene regulation." Weinberg noted that Jothi received the NIEHS Early Career Award in November 2009, less than a year after his arrival.

R. Scott Williams - Structural Biologist

Williams (http://www.niehs.nih.gov/research/atniehs/labs/lsb/genome/index.cfm) is the principal investigator of the Genome Stability Structural Biology Group in the Laboratory of Structural Biology (LSB)(http://www.niehs.nih.gov/research/atniehs/labs/lsb/index.cfm). He uses techniques such as x-ray crystallography, small angle x-ray scattering, and biochemical analyses to examine protein complexes that sense, signal, and repair chromosomal double strand breaks (DSBs). Without repair, DSBs can lead to chromosomal rearrangements, genome instability, and cancer.

"Scott is an expert in the structural biology of proteins involved in the repair of DNA damage resulting from environmental stress," said Tom Kunkel, Ph.D., chief of the LSB. "His expertise nicely complements the research being performed by a number of other local and NIH Bethesda scientific groups," Kunkel explained. "Scott's presence provides the opportunity to develop the type of synergistic interactions among investigators that DIR values so much."

(Laura Hall is a biologist in the NIEHS Laboratory of Pharmacology currently on detail as a writer for the Environmental Factor.)

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