In 2020, the largest protest movement in US history happened in the wake of the murder of George Floyd. In response, the American Institute of Physics (AIP) conducted oral history interviews with prominent African-American physicists, seeking to understand their perspectives on dismantling systemic racism in the physics community. Oral histories provide an alternate view of history that cannot be quantified and exists outside of the normative view of truth; was this an effective strategy for inciting change in a discipline that pedestals objective truths over subjective truths? Moreover, does limiting interviews to notable, outstanding African-American physicists limit the AIP’s ability to capture the range of truths systemically experienced by African-American physicists? This project will investigate the strengths and drawbacks of these oral histories, using primary sources such as National Science Foundation censuses and secondary sources to analyze whether these physicists’ experiences can be generalized and if this generalization holds power over the scientific doctrine of objective physical truths. The treatment of the African-American experience as a monolith dilutes the intentions of the oral histories by withering away intersectional aspects of the experience. As a result, the interviews lack an intersectional and class analysis that reflects how American physics has interwoven with a racial capitalist political economy. By providing an intersectional historical analysis of 20th-century physics, this paper will aim to rethink how large trends are historicized with individual narratives. The framework used to incorporate and critique oral histories in research simultaneously can serve as a model for future history of science research.

To form Human Immunodeficiency Virus type 1 (HIV-1) virions, the HIV-1 Gag polyprotein multimerizes, traffics to the cell membrane, assembles into virions, and buds as viral particles. HIV uses the infected cell proteins to support viral assembly and export from the cell. Although some cellular proteins have been identified that participate in viral assembly and budding, the spatial and temporal "cellular proteome" is not known. Insights as to the order of proteins involved in facilitating assembly and budding provide information on viral infection and potential therapy targets. I am utilizing a split-APEX2-mediated proximity labeling method to identify which host factors interact with Gag during assembly. The basis of the method is splitting APEX2 into two segments encoded into separate Gag sequences so that the APEX2 segments rejoin for complete enzymatic function when Gag dimerizes and multimerizes. Once the APEX2 enzyme reconstitutes, we activate it to biotinylate cellular host proteins within ~20 nm of Gag during the processes of virion formation. I aim to deliver this system to primary human CD4+ T-cells and macrophages via two lentiviral vectors containing transgenes for either AP-Gag-P2A-EGFP or EX-Gag-P2A-mCherry. Cells express the dual fluorescence markers EGFP and mCherry if both Split-APEX2 domains are present, and we enrich these cells by cell sorting. APEX2 is restored and enzymatically active, allowing proximity-dependent biotinylation of Gag-host cell proteins for SILAC-based quantitative proteomic mapping during virion assembly. We are using this method to quantitatively map the Gag-host protein "interactome" in the infected cellular microenvironment in subtypes of human primary CD4+ T-cells and macrophages. Therefore, this research studies Gag interactions of potential HIV-1 host dependency factors in CD4+ T-cells and macrophages, the natural cell populations for HIV-1 infection. Previously, we conducted a similar study in HEK293Ts, and we anticipate elucidating a similar Gag-host cell protein analysis with this study.

The HIV-1 gag polyprotein consists of the core structural proteins of the virus. During the late stages of viral replication, gag assembles beneath the plasma membrane into a curved immature hexagonal lattice. This process is primarily mediated by the capsid (CA) and spacer peptide 1 (SP1) domains which form a six-helix bundle with the assistance of the naturally occurring small molecule inositol hexakisphosphate (IP₆). Following budding of the immature virion, the HIV-1 protease cleaves the gag domains and CA protein assembles into a mature conical capsid, the protective shell of the virus. Disruption of CA assembly has been shown to inhibit viral replication and in turn has led to the development of the novel antiretroviral drug lenacapavir. While lenacapavir can bind mature capsid cores, the exact mode in which this drug impacts viral assembly and specifically interacts with immature CA remains unclear. My project aims to investigate the effect of lenacapavir and chemically and structurally related analogues of this drug, which have been designed and synthesized by a collaborator, on immature CA assembly in vitro. For this study I optimized the expression and purification of a gag construct that spans the CA to NC domains with an additional N-terminal Serine residue (s-CANC). I transformed E. coli cells with a plasmid containing the s-CANC construct and then overexpressed the protein. I optimized the purification protocol involving gel filtration, ion exchange and immobilized metal affinity chromatography. The purified s-CANC was then used to perform assembly assays using IP₆ in the absence and presence of lenacapavir and the analogues. The formation of immature capsid cores was confirmed via negative staining electron microscopy. Insights from these studies aim to provide a better understanding of how lenacapavir impacts the assembly of immature CA in addition to aiding the development of new capsid targeting antiretroviral drugs.

The HIV-1 capsid is a conical lattice comprised of over 1500 monomeric capsid proteins (CA) that acts as a protective casing for the viral genome. Assembly of the capsid core is driven by the small negatively charged molecule, inositol phosphate (IP6), which interacts with positively charged CA residues. The ability to inhibit viral replication through the disruption of CA assembly has been demonstrated by the novel capsid binding antiretroviral, lenacapavir. Antiretroviral research is also being done on “clickable” compounds which should covalently interact with CA through a Sulfur (VI) Fluoride Exchange (SuFEx) reaction. Our lab has received lenacapavir analogues as well as compounds that potentially interact with CA via a SuFEx reaction (SuFEx compounds). My aim is to assess the impact of lenacapavir and the synthesized analogues on CA assembly, in addition to validating the ability of 15 promising SuFEx compounds to covalently bind CA. In preparation, I transformed E. coli cells with a plasmid containing the HIV-1 CA sequence and induced expression using IPTG. The cells were then pelleted, lysed and the protein purified utilizing gel filtration, anion- and cation-exchange chromatography. Assembly of the purified CA was induced in vitro by the addition of IP6 in both the absence and presence of lenacapavir and the analogues. Relative to lenacapavir, two analogues promoted assembly to a greater extent, while one performed on par and three enhanced assembly to a lesser extent. These analogues will be further studied to determine antiviral activity. Samples of CA in the presence of the SuFEx compounds have also been prepared and sent for mass spectrometry analysis. It will then be determined which of the SuFEx compounds bind CA covalently in vitro and may aid in the development of new capsid targeting antiretrovirals.