Fly-CURE, a multi-institutional CURE using Drosophila, increases students' confidence, sense of belonging, and persistence in research.

The Fly-CURE is a genetics-focused multi-institutional Course-Based Undergraduate Research Experience (CURE) that provides undergraduate students with hands-on research experiences within a course. Through the Fly-CURE, undergraduate students at diverse types of higher education institutions across the United States map and characterize novel mutants isolated from a genetic screen in Drosophila melanogaster. To date, more than 20 mutants have been studied across 20 institutions, and our scientific data have led to eleven publications with more than 500 students as authors. To evaluate the impact of the Fly-CURE experience on students, we developed and validated assessment tools to identify students' perceived research self-efficacy, sense of belonging in science, and intent to pursue additional research opportunities. Our data, collected over three academic years and involving 14 institutions and 480 students, show gains in these metrics after completion of the Fly-CURE across all student subgroups analyzed, including comparisons of gender, academic status, racial and ethnic groups, and parents' educational background. Importantly, our data also show differential gains in the areas of self-efficacy and interest in seeking additional research opportunities between Fly-CURE students with and without prior research experience, illustrating the positive impact of research exposure (dosage) on student outcomes. Altogether, our data indicate that the Fly-CURE experience has a significant impact on students' efficacy with research methods, sense of belonging to the scientific research community, and interest in pursuing additional research experiences.

Fly-CURE, a Multi-institutional CURE using Drosophila, Increases Students' Confidence, Sense of Belonging, and Persistence in Research.

The Fly-CURE is a genetics-focused multi-institutional Course-Based Undergraduate Research Experience (CURE) that provides undergraduate students with hands-on research experiences within a course. Through the Fly-CURE, undergraduate students at diverse types of higher education institutions across the United States map and characterize novel mutants isolated from a genetic screen in Drosophila melanogaster. To evaluate the impact of the Fly-CURE experience on students, we developed and validated assessment tools to identify students' perceived research self-efficacy, sense of belonging in science, and intent to pursue additional research opportunities. Our data show gains in these metrics after completion of the Fly-CURE across all student subgroups analyzed, including comparisons of gender, academic status, racial and ethnic groups, and parents' educational background. Importantly, our data also show differential gains in the areas of self-efficacy and interest in seeking additional research opportunities between Fly-CURE students with and without prior research experience, illustrating the positive impact of research exposure (dosage) on student outcomes. Altogether, our data indicate that the Fly-CURE experience has a significant impact on students' efficacy with research methods, sense of belonging to the scientific community, and interest in pursuing additional research experiences.

Genetic Mapping of a new Hippo allele, HpoN.1.2, in Drosophila melanogaster.

Genetic screens provide a mechanism to identify genes involved with different cellular and organismal processes. Using a Flp/FRT screen in the Drosophila eye we identified mutations that result in alterations and de-regulation of cell growth and division. From this screen a group of undergraduate researchers part of the Fly-CURE consortium mapped and characterized a new allele of the gene Hippo, HpoN.1.2.

Centriolar SAS-7 acts upstream of SPD-2 to regulate centriole assembly and pericentriolar material formation.

The centriole/basal body is a eukaryotic organelle that plays essential roles in cell division and signaling. Among five known core centriole proteins, SPD-2/Cep192 is the first recruited to the site of daughter centriole formation and regulates the centriolar localization of the other components in C. elegans and in humans. However, the molecular basis for SPD-2 centriolar localization remains unknown. Here, we describe a new centriole component, the coiled-coil protein SAS-7, as a regulator of centriole duplication, assembly and elongation. Intriguingly, our genetic data suggest that SAS-7 is required for daughter centrioles to become competent for duplication, and for mother centrioles to maintain this competence. We also show that SAS-7 binds SPD-2 and regulates SPD-2 centriolar recruitment, while SAS-7 centriolar localization is SPD-2-independent. Furthermore, pericentriolar material (PCM) formation is abnormal in sas-7 mutants, and the PCM-dependent induction of cell polarity that defines the anterior-posterior body axis frequently fails. We conclude that SAS-7 functions at the earliest step in centriole duplication yet identified and plays important roles in the orchestration of centriole and PCM assembly.

A survey of new temperature-sensitive, embryonic-lethal mutations in C. elegans: 24 alleles of thirteen genes.

To study essential maternal gene requirements in the early C. elegans embryo, we have screened for temperature-sensitive, embryonic lethal mutations in an effort to bypass essential zygotic requirements for such genes during larval and adult germline development. With conditional alleles, multiple essential requirements can be examined by shifting at different times from the permissive temperature of 15°C to the restrictive temperature of 26°C. Here we describe 24 conditional mutations that affect 13 different loci and report the identity of the gene mutations responsible for the conditional lethality in 22 of the mutants. All but four are mis-sense mutations, with two mutations affecting splice sites, another creating an in-frame deletion, and one creating a premature stop codon. Almost all of the mis-sense mutations affect residues conserved in orthologs, and thus may be useful for engineering conditional mutations in other organisms. We find that 62% of the mutants display additional phenotypes when shifted to the restrictive temperature as L1 larvae, in addition to causing embryonic lethality after L4 upshifts. Remarkably, we also found that 13 out of the 24 mutations appear to be fast-acting, making them particularly useful for careful dissection of multiple essential requirements. Our findings highlight the value of C. elegans for identifying useful temperature-sensitive mutations in essential genes, and provide new insights into the requirements for some of the affected loci.

Seawi--a sea urchin piwi/argonaute family member is a component of MT-RNP complexes.

The piwi/argonaute family of proteins is involved in key developmental processes such as stem cell maintenance and axis specification through molecular mechanisms that may involve RNA silencing. Here we report on the cloning and characterization of the sea urchin piwi/argonaute family member seawi. Seawi is a major component of microtubule-ribonucleoprotein (MT-RNP) complexes isolated from two different species of sea urchin, Strongylocentrotus purpuratus and Paracentrotus lividus. Seawi co-isolates with purified ribosomes, cosediments with 80S ribosomes in sucrose density gradients, and binds microtubules. Seawi possesses the RNA binding motif common to piwi family members and binds P. lividus bep4 mRNA, a transcript that co-isolates with MT-RNP complexes and whose translation product has been shown to play a role in patterning the animal-vegetal axis. Indirect immunofluorescence studies localized seawi to the cortex of unfertilized eggs within granule-like particles, the mitotic spindle during cell division, and the small micromeres where its levels were enriched during the early cleavage stage. Lastly, we discuss how seawi, as a piwi/argonaute family member, may play a fundamentally important role in sea urchin animal-vegetal axis formation and stem cell maintenance.

Centrosome maturation and mitotic spindle assembly in C. elegans require SPD-5, a protein with multiple coiled-coil domains.

The maternally expressed C. elegans gene spd-5 encodes a centrosomal protein with multiple coiled-coil domains. During mitosis in mutants with reduced levels of SPD-5, microtubules assemble but radiate from condensed chromosomes without forming a spindle, and mitosis fails. SPD-5 is required for the centrosomal localization of gamma-tubulin, XMAP-215, and Aurora A kinase family members, but SPD-5 accumulates at centrosomes in mutants lacking these proteins. Furthermore, SPD-5 interacts genetically with a dynein heavy chain. We propose that SPD-5, along with dynein, is required for centrosome maturation and mitotic spindle assembly.

Cytoskeletal regulation by the Nedd8 ubiquitin-like protein modification pathway.

The Nedd8 ubiquitin-like protein modification pathway regulates cell-cycle progression. Our analysis of Nedd8 requirements during Caenorhabditis elegans embryogenesis indicates that the cytoskeleton is another target. Nedd8 conjugation negatively regulated contractility of the microfilament-rich cell cortex during pronuclear migration and again during cytokinesis. The Nedd8 pathway also was required after meiosis to negatively regulate katanin, a microtubule-severing complex, permitting the assembly of a large mitotic spindle. We propose that Nedd8-modified cullin, as part of an E3 ubiquitin ligase complex, targets katanin for degradation during the transition from meiosis to mitosis.