Robert E. Kingston

Robert E. Kingston (born in 1954) is an American biochemist and geneticist who studies the functional and regulatory role nucleosomes play in gene expression, specifically during early development. After receiving his PhD in 1981 and completing post-doctoral research, Kingston became an assistant professor at Massachusetts General Hospital in 1985, where he started a research laboratory focused on understanding chromatin structure with regards to transcriptional regulation. In addition to being a professor of genetics at Harvard Medical School, Kingston frequently organizes conferences and performs editorials on his research interests. He found that this happens because of the specific presence and location of pause sites, located 90 and 91 bases from the P1 promoter, which are sensitive to the presence of nusA protein and the concentration of the regulatory nucleotide guanosine tetraphosphate. He also found that expression of HSP70 is dependent on physiological stresses. Analyzing the gene sequences showed that heat shock, cadmium induction, and metallothionein II responsiveness are needed for HSP70 gene expression during the primary level of transcription. He observed that while the physiological factors have a role on one domain (distal) of the HSP70 promoter, the other domain (proximal) is more responsive to serum stimulation. In vitro cell-free systems that have heat-induced activation of human heat-shock factor (HSF) were used to determine that at 43 °C, HSF undergoes post-translational modification which then allows it to bind to a specific DNA sequence, HSE.

SWI/SNF subunits of chromatin remodeling Kingston's primary research interests surround chromatin remodeling, and his breakthroughs within the field began when he discovered the functional subunit responsibilities of SWI/SNF, a chromatin remodeling complex that causes specific transcription factors to bind to nucleosomal DNA. He discovered that two SWI/SNF subunits, BRG1 and BAF155, along with EKLF zinc-finger DNA-binding domains (DBDs) can be used to remodel chromatin, meaning that these specific domains of SWI/SNF have an effect on transcription factor-directed nucleosome remodeling. This is because a purified human SWI/SNF complex mediated the ATP-dependent disruption of a nucleosomal barrier, resulting in SWI/SNF activators (GAL4-VP16 and GAL 4-AH) binding onto the nucleosome core. Since the TATA sequence is inside a nucleosome, adding ATP will cause human SWI/SNF to recognize its chromatin structure and alter the nucleosomal DNA sequence so that the TPB can be accessed and bind to it. Kingston found that in order to form the complex that silences chromatin remodeling, it must be stable and compact. Through electron microscopy, he found that the components of PRC1 induce compaction of nucleosomal arrays. Noting that Polycomb proteins factor into stem cell renewal and the formation of diseases, Kingston's discovery of direct interactions (Ezh2 subunit) and PRC2 cofactors (Gtl2 RNA) contributed to identifying the function of Polycomb proteins within the genome. He established a protocol, Proteomics of Isolated Chromatin Segments (PICh), in which a specific nucleic acid probe is used to isolate genomic DNA with regards to the quantity and purity of associated proteins. These two methods use a precipitate to introduce plasmid DNA into monolayer cell cultures. He was able to genome map NEAT1 and MALAT (both lncRNAs) and found that they localize overactive genes. to regulate endoderm differentiation transcriptionally. He discovered that the Ikaros-NuRD complex is able to target chromatin remodeling and histone deacetylation complexes in vivo. Specifically, multiprotein complexes that were used for transcriptional regulation were found to variably acetylate or deacetylate nucleosomes, or alter nucleosome structure when ATP is present. Through in vitro studies with CHD3 and CHD4 proteins with ATPase domains found in chromatin remodelling factors, Kingston established that there is a functional and physical link between nucleosome remodeling proteins and histone deacetylases’ chromatin-modifying features.

Selected review publications The CBX family of proteins in transcriptional repression and memory Cooperation between complexes that regulate chromatin structure and transcription Mechanisms of polycomb gene silencing: knowns and unknowns Occupying chromatin: Polycomb mechanisms for getting to genomic targets, stopping transcriptional traffic, and staying put ATP-dependent remodeling and acetylation as regulators of chromatin fluidity Characterization of the piRNA complex from rat testes Comparative analysis of metazoan chromatin organization