The 5-cap and the poly(A) tail act synergistically to increase the translational efficiency of eukaryotic mRNAs, which suggests that these two mRNA elements communicate during translation. We report here that the cap-associated eukaryotic initiation factors (eIFs), i.e. the two isoforms of the cap-binding complex (eIF-4F and eIF-iso4F) and eIF-4B, bind to the poly(A)-binding protein (PABP) both in the presence and absence of poly(A) RNA. The interactions between PABP and eIF-4F, eIF-iso4F, and eIF-4B were measured in the absence of poly(A) RNA using far Western analysis and confirmed by direct fluorescence titration studies. The functional consequence of the interaction between these initiation factors and PABP was examined using RNA binding assays and RNA mobility shift analysis. eIF-4F, eIF-iso4F, and eIF-4B promoted PABP activity through a shift in its equilibrium affinity for poly(A). eIF-iso4G, the large subunit of eIF-iso4F, was the subunit responsible for the interaction between eIF-iso4F and PABP and was the subunit that promoted PABP RNA binding activity. Truncation analysis of eIF-iso4G indicated that a domain close to its N-terminal end appeared to be involved in binding PABP. These results suggest that the interaction between PABP and eIF-4B and eIF-iso4G may be involved in mediating the functional co-dependence observed between the cap and the poly(A) tail during translation.Most eukaryotic mRNAs contain a cap (m 7

Native Americans are underrepresented in science, technology, engineering, and math (STEM) careers. We examine communal goal incongruence-the mismatch between students' emphasis on communal work goals and the noncommunal culture of STEM-as a possible factor in this underrepresentation. First, we surveyed 80 Native American STEM freshmen and found they more highly endorsed communal goals than individualistic work goals. Next, we surveyed 96 Native American and White American students in STEM and non-STEM majors and confirmed that both Native American men and women in STEM highly endorsed communal goals. In a third study, we conducted a follow-up survey and in-depth interviews with a subset of Native American STEM students in their second semester to assess their experiences of belonging uncertainty, intrinsic motivation, persistence intentions, and perceived performance in STEM as a function of their initial communal work goals. Results demonstrate the prominence of communal goals among incoming Native American freshman (especially compared with White male STEM majors) and the connection between communal goals and feelings of belonging uncertainty, low motivation, and perceived poor performance 1 semester later. The interview data illustrate that these issues are particularly salient for students raised within tribal communities, and that a communal goal orientation is not just a vague desire to "help others," but a commitment to helping their tribal communities. The interviews also highlight the importance of student support programs for fostering feelings of belonging. We end by discussing implications for interventions and institutional changes that may promote Native American student retention in STEM.

There is an increasing need for students in the biological sciences to build a strong foundation in quantitative approaches to data analyses. Although most science, engineering, and math field majors are required to take at least one statistics course, statistical analysis is poorly integrated into undergraduate biology course work, particularly at the lower-division level. Elements of statistics were incorporated into an introductory biology course, including a review of statistics concepts and opportunity for students to perform statistical analysis in a biological context. Learning gains were measured with an 11-item statistics learning survey instrument developed for the course. Students showed a statistically significant 25% (p Ͻ 0.005) increase in statistics knowledge after completing introductory biology. Students improved their scores on the survey after completing introductory biology, even if they had previously completed an introductory statistics course (9%, improvement p Ͻ 0.005). Students retested 1 yr after completing introductory biology showed no loss of their statistics knowledge as measured by this instrument, suggesting that the use of statistics in biology course work may aid long-term retention of statistics knowledge. No statistically significant differences in learning were detected between male and female students in the study.

The isozyme form of plant eukaryotic initiation factor 4F (eIF(iso)4F) contains two subunits: p28, a cap-binding protein, and p86. To identify the functional domains of p86, truncations of the p86 cDNA were made, and the protein was expressed in Escherichia coli and purified. The deletion mutants were tested for the ability to bind the p28 subunit by two methods. In addition, these deletion mutants were evaluated in vitro by the ability to catalyze eIF4A and RNA-dependent ATP hydrolysis and to support polypeptide synthesis. The loss of the ability to bind p28 occurs within the first 90 amino acids of the N terminus and abrogates the ability of p86 to participate in translation initiation and bind to eIF4A, but does not affect ATP hydrolysis. Up to 299 amino acid residues from the C terminus of p86 must be deleted before an effect is observed on the ATP hydrolysis activity. Thus, the p28 binding and ATP hydrolysis activities appear to lie on two separate domains and are functionally uncoupled. In addition, at least a portion of the eIF4A binding domain appears to be in close proximity to the p28 binding domain and is also uncoupled from the ATP hydrolysis activity.

Pestalotiopsis microspora, isolate NE-32, is an endophyte of the Himalayan yew (Taxus wallichiana) that produces taxol, an important chemotherapeutic drug used in the treatment of breast and ovarian cancers. Conditions were determined to induce the perfect stage (teleomorph) of this organism in the laboratory as a critical first step to study inheritance of taxol biosynthetic genes. The perfect stage of Pestalotiopsis microspora NE-32 forms in a period of 3-6 weeks on water agarose with dried yew needles at 16-20 SC with 12 h of light per day. Morphological analysis of the teleomorph and sequencing of the 18S rDNA indicates that Pestalosphaeria hansenii is the perfect stage of Pestalotiopsis microspora. Only certain plants (e.g. yews, some pines, pecan, oat and some barley cultivars) allow the production of perithecia. Exhaustive methylene chloride extraction of yew (Taxus cuspidata) needles removes their capacity to induce production of perithecia. The methylene chloride extract is able to induce formation of perithecia by strain NE-32 in a bioassay system utilizing the sterilized sheaths of the Cholla cactus (Opuntia bigelovii) spine, indicating that a chemical compound(s) in yew stimulates the formation of the perfect stage. This hydrophobic plant compound(s) has been designated the perithecial-stimulating factor (PSF). The data suggest that plant products may play a role in regulating the biology of endophytic microbes.