Lauren Goins

All Publications

• Wnt signaling couples G2 phase control with differentiation during hematopoiesis Goins, L. M., Girard, J. R., Mondal, B., Buran, S., Su, C. C., Tang, R., Biswas, T., Banerjee, U. BioRxiv. 2023

  Abstract

  During homeostasis, a critical balance is maintained between myeloid-like progenitors and their differentiated progeny, which function to mitigate stress and innate immune challenges. The molecular mechanisms that help achieve this balance are not fully understood. Using genetic dissection in Drosophila, we show that a Wnt6/EGFR-signaling network simultaneously controls progenitor growth, proliferation, and differentiation. Unlike G1-quiescence of stem cells, hematopoietic progenitors are blocked in the G2 phase by a β-catenin-independent Wnt6 pathway that restricts Cdc25 nuclear entry and promotes cell growth. Canonical β-catenin-dependent Wnt6 signaling is spatially confined to mature progenitors through localized activation of the tyrosine-kinases EGFR and Abl, which promote nuclear entry of β-catenin and facilitate exit from G2. This strategy combines transcription-dependent and - independent forms of both Wnt6 and EGFR pathways to create a direct link between cell-cycle control and differentiation. This unique combinatorial strategy employing conserved components may underlie homeostatic balance and stress response in mammalian hematopoiesis.

• Intermediate progenitor cells provide a transition between hematopoietic progenitors and their differentiated descendants DEVELOPMENT Spratford, C. M., Goins, L. M., Chi, F., Girard, J. R., Macias, S. N., Ho, V. W., Banerjee, U. 2021; 148 (24)

  Abstract

  Genetic and genomic analysis in Drosophila suggests that hematopoietic progenitors likely transition into terminal fates via intermediate progenitors (IPs) with some characteristics of either, but perhaps maintaining IP-specific markers. In the past, IPs have not been directly visualized and investigated owing to lack of appropriate genetic tools. Here, we report a Split GAL4 construct, CHIZ-GAL4, that identifies IPs as cells physically juxtaposed between true progenitors and differentiating hemocytes. IPs are a distinct cell type with a unique cell-cycle profile and they remain multipotent for all blood cell fates. In addition, through their dynamic control of the Notch ligand Serrate, IPs specify the fate of direct neighbors. The Ras pathway controls the number of IP cells and promotes their transition into differentiating cells. This study suggests that it would be useful to characterize such intermediate populations of cells in mammalian hematopoietic systems.

  View details for DOI 10.1242/dev.200216

  View details for Web of Science ID 000755716500014

  View details for PubMedID 34918741

  View details for PubMedCentralID PMC8722385

• Paths and pathways that generate cell-type heterogeneity and developmental progression in hematopoiesis ELIFE Girard, J. R., Goins, L. M., Vuu, D. M., Sharpley, M. S., Spratford, C. M., Mantri, S. R., Banerjee, U. 2021; 10

  Abstract

  Mechanistic studies of Drosophila lymph gland hematopoiesis are limited by the availability of cell-type-specific markers. Using a combination of bulk RNA-Seq of FACS-sorted cells, single-cell RNA-Seq, and genetic dissection, we identify new blood cell subpopulations along a developmental trajectory with multiple paths to mature cell types. This provides functional insights into key developmental processes and signaling pathways. We highlight metabolism as a driver of development, show that graded Pointed expression allows distinct roles in successive developmental steps, and that mature crystal cells specifically express an alternate isoform of Hypoxia-inducible factor (Hif/Sima). Mechanistically, the Musashi-regulated protein Numb facilitates Sima-dependent non-canonical, and inhibits canonical, Notch signaling. Broadly, we find that prior to making a fate choice, a progenitor selects between alternative, biologically relevant, transitory states allowing smooth transitions reflective of combinatorial expressions rather than stepwise binary decisions. Increasingly, this view is gaining support in mammalian hematopoiesis.

  View details for DOI 10.7554/eLife.67516.sa2

  View details for Web of Science ID 000723147200001

  View details for PubMedID 34713801

  View details for PubMedCentralID PMC8610493

• Drosophila as a Genetic Model for Hematopoiesis GENETICS Banerjee, U., Girard, J. R., Goins, L. M., Spratford, C. M. 2019; 211 (2): 367-417

  Abstract

  In this FlyBook chapter, we present a survey of the current literature on the development of the hematopoietic system in Drosophila The Drosophila blood system consists entirely of cells that function in innate immunity, tissue integrity, wound healing, and various forms of stress response, and are therefore functionally similar to myeloid cells in mammals. The primary cell types are specialized for phagocytic, melanization, and encapsulation functions. As in mammalian systems, multiple sites of hematopoiesis are evident in Drosophila and the mechanisms involved in this process employ many of the same molecular strategies that exemplify blood development in humans. Drosophila blood progenitors respond to internal and external stress by coopting developmental pathways that involve both local and systemic signals. An important goal of these Drosophila studies is to develop the tools and mechanisms critical to further our understanding of human hematopoiesis during homeostasis and dysfunction.

  View details for DOI 10.1534/genetics.118.300223

  View details for Web of Science ID 000458574800002

  View details for PubMedID 30733377

  View details for PubMedCentralID PMC6366919

• A novel tropomyosin isoform functions at the mitotic spindle and Golgi in Drosophila MOLECULAR BIOLOGY OF THE CELL Goins, L. M., Mullins, R. 2015; 26 (13): 2491-2504

  Abstract

  Most eukaryotic cells express multiple isoforms of the actin-binding protein tropomyosin that help construct a variety of cytoskeletal networks. Only one nonmuscle tropomyosin (Tm1A) has previously been described in Drosophila, but developmental defects caused by insertion of P-elements near tropomyosin genes imply the existence of additional, nonmuscle isoforms. Using biochemical and molecular genetic approaches, we identified three tropomyosins expressed in Drosophila S2 cells: Tm1A, Tm1J, and Tm2A. The Tm1A isoform localizes to the cell cortex, lamellar actin networks, and the cleavage furrow of dividing cells--always together with myosin-II. Isoforms Tm1J and Tm2A colocalize around the Golgi apparatus with the formin-family protein Diaphanous, and loss of either isoform perturbs cell cycle progression. During mitosis, Tm1J localizes to the mitotic spindle, where it promotes chromosome segregation. Using chimeras, we identified the determinants of tropomyosin localization near the C-terminus. This work 1) identifies and characterizes previously unknown nonmuscle tropomyosins in Drosophila, 2) reveals a function for tropomyosin in the mitotic spindle, and 3) uncovers sequence elements that specify isoform-specific localizations and functions of tropomyosin.

  View details for DOI 10.1091/mbc.E14-12-1619

  View details for Web of Science ID 000357053400009

  View details for PubMedID 25971803

  View details for PubMedCentralID PMC4571303

• Arp2/3 Complex and Cofilin Modulate Binding of Tropomyosin to Branched Actin Networks CURRENT BIOLOGY Hsiao, J. Y., Goins, L. M., Petek, N. A., Mullins, R. 2015; 25 (12): 1573-1582

  Abstract

  Tropomyosins are coiled-coil proteins that bind actin filaments and regulate multiple cytoskeletal functions, including actin network dynamics near the leading edge of motile cells. Previous work demonstrated that tropomyosins inhibit actin nucleation by the Arp2/3 complex and prevent filament disassembly by cofilin. We find that the Arp2/3 complex and cofilin, in turn, regulate the binding of tropomyosin to actin filaments. Using fluorescence microscopy, we show that tropomyosin (non-muscle Drosophila Tm1A) polymerizes along actin filaments, starting from "nuclei" that appear preferentially on ADP-bound regions of the filament, near the pointed end. Tropomyosin fails to bind dendritic actin networks created in vitro by the Arp2/3 complex, in part because the Arp2/3 complex blocks pointed ends. Cofilin promotes phosphate dissociation and severs filaments, generating new pointed ends and rendering Arp2/3-generated networks competent to bind tropomyosin. Tropomyosin's attraction to pointed ends reflects a strong preference for conformations localized to that region of the filament and reveals a basic molecular mechanism by which lamellipodial actin networks are insulated from the effects of tropomyosin.

  View details for DOI 10.1016/j.cub.2015.04.038

  View details for Web of Science ID 000356562500017

  View details for PubMedID 26028436

  View details for PubMedCentralID PMC4470865

• Comparative analysis of tools for live cell imaging of actin network architecture. Bioarchitecture Belin, B. J., Goins, L. M., Mullins, R. D. 2014; 4 (6): 189-202

  Abstract

  Fluorescent derivatives of actin and actin-binding domains are powerful tools for studying actin filament architecture and dynamics in live cells. Growing evidence, however, indicates that these probes are biased, and their cellular distribution does not accurately reflect that of the cytoskeleton. To understand the strengths and weaknesses of commonly used live-cell probes--fluorescent protein fusions of actin, Lifeact, F-tractin, and actin-binding domains from utrophin--we compared their distributions in cells derived from various model organisms. We focused on five actin networks: the peripheral cortex, lamellipodial and lamellar networks, filopodial bundles, and stress fibers. Using phalloidin as a standard, we identified consistent biases in the distribution of each probe. The localization of F-tractin is the most similar to that of phalloidin but induces organism-specific changes in cell morphology. Both Lifeact and GFP-actin concentrate in lamellipodial actin networks but are excluded from lamellar networks and filopodia. In contrast, the full utrophin actin-binding domain (Utr261) binds filaments of the lamellum but only weakly localizes to lamellipodia, while a shorter variant (Utr230) is restricted to the most stable subpopulations of actin filaments: cortical networks and stress fibers. In some cells, Utr230 also detects Golgi-associated filaments, previously detected by immunofluorescence but not visible by phalloidin staining. Consistent with its localization, Utr230 exhibits slow rates of fluorescence recovery after photobleaching (FRAP) compared to F-tractin, Utr261 and Lifeact, suggesting that it may be more useful for FRAP- and photo-activation-based studies of actin network dynamics.

  View details for DOI 10.1080/19490992.2014.1047714

  View details for PubMedID 26317264

  View details for PubMedCentralID PMC4914014

• Prior exposure to an attenuated Listeria vaccine does not reduce immunogenicity: pre-clinical assessment of the efficacy of a Listeria vaccine in the induction of immune responses against HIV. Journal of immune based therapies and vaccines Whitney, J. B., Mirshahidi, S., Lim, S. Y., Goins, L., Ibegbu, C. C., Anderson, D. C., Raybourne, R. B., Frankel, F. R., Lieberman, J., Ruprecht, R. M. 2011; 9: 2

  Abstract

  We have evaluated an attenuated Listeria monocytogenes (Lm) candidate vaccine vector in nonhuman primates using a delivery regimen relying solely on oral vaccination. We sought to determine the impact of prior Lm vector exposure on the development of new immune responses against HIV antigens.Two groups of rhesus macaques one Lm naive, the other having documented prior Lm vector exposures, were evaluated in response to oral inoculations of the same vector expressing recombinant HIV-1 Gag protein. The efficacy of the Lm vector was determined by ELISA to assess the generation of anti-Listerial antibodies; cellular responses were measured by HIV-Gag specific ELISpot assay. Our results show that prior Lm exposures did not diminish the generation of de novo cellular responses against HIV, as compared to Listeria-naïve monkeys. Moreover, empty vector exposures did not elicit potent antibody responses, consistent with the intracellular nature of Lm.The present study demonstrates in a pre-clinical vaccine model, that prior oral immunization with an empty Lm vector does not diminish immunogenicity to Lm-expressed HIV genes. This work underscores the need for the continued development of attenuated Lm as an orally deliverable vaccine.

  View details for DOI 10.1186/1476-8518-9-2

  View details for PubMedID 21244649

  View details for PubMedCentralID PMC3033796

• Molecularly cloned SHIV-1157ipd3N4: a highly replication-competent, mucosally transmissible R5 simian-human immunodeficiency virus encoding HIV clade C env JOURNAL OF VIROLOGY Song, R. J., Chenine, A., Rasmussen, R. A., Ruprecht, C. R., Mirshahidi, S., Grisson, R. D., Xu, W., Whitney, J. B., Goins, L. M., Ong, H., Li, P., Shai-Kobiler, E., Wang, T., McCann, C. M., Zhang, H., Wood, C., Kankasa, C., Secor, W. E., McClure, H. M., Strobert, E., Else, J. G., Ruprecht, R. M. 2006; 80 (17): 8729-8738

  Abstract

  Human immunodeficiency virus type 1 (HIV-1) clade C causes >50% of all HIV infections worldwide, and an estimated 90% of all transmissions occur mucosally with R5 strains. A pathogenic R5 simian-human immunodeficiency virus (SHIV) encoding HIV clade C env is highly desirable to evaluate candidate AIDS vaccines in nonhuman primates. To this end, we generated SHIV-1157i, a molecular clone from a Zambian infant isolate that carries HIV clade C env. SHIV-1157i was adapted by serial passage in five monkeys, three of which developed peripheral CD4(+) T-cell depletion. After the first inoculated monkey developed AIDS at week 137 postinoculation, transfer of its infected blood to a naïve animal induced memory T-cell depletion and thrombocytopenia within 3 months in the recipient. In parallel, genomic DNA from the blood donor was amplified to generate the late proviral clone SHIV-1157ipd3. To increase the replicative capacity of SHIV-1157ipd3, an extra NF-kappaB binding site was engineered into its 3' long terminal repeat, giving rise to SHIV-1157ipd3N4. This virus was exclusively R5 tropic and replicated more potently in rhesus peripheral blood mononuclear cells than SHIV-1157ipd3 in the presence of tumor necrosis factor alpha. Rhesus macaques of Indian and Chinese origin were next inoculated intrarectally with SHIV-1157ipd3N4; this virus replicated vigorously in both sets of monkeys. We conclude that SHIV-1157ipd3N4 is a highly replication-competent, mucosally transmissible R5 SHIV that represents a valuable tool to test candidate AIDS vaccines targeting HIV-1 clade C Env.

  View details for DOI 10.1128/JVI.00558-06

  View details for Web of Science ID 000239934500040

  View details for PubMedID 16912320

  View details for PubMedCentralID PMC1563858

• Effects of temperature and membrane fluidity on motile keratocytes: A quantitative analysis of speed and morphology Wilson, C. A., Ream, R. A., Goins, L. M., Theriot, J. A. BIOPHYSICAL SOCIETY. 2004: 569A

  View details for Web of Science ID 000187971202935

• The role of membrane fluidity in the motility of fish keratocytes Ream, R. A., Goins, L., Theriot, J. A. AMER SOC CELL BIOLOGY. 2001: 170A

  View details for Web of Science ID 000172372500924