Hasil untuk "Biology (General)"

Konstantinos Nakos, Sithara Wijeratne, Michael Blower et al.

ABSTRACT The Aurora B kinase-containing Chromosomal Passenger Complex (CPC) is an essential regulator of cytokinesis, the final and irreversible step of cell division. During anaphase, the CPC concentrates at the spindle midzone - a bundle of overlapping antiparallel microtubules organized at the cell center. How CPC is selectively enriched at the midzone within the dense, heterogeneous, and dynamic spindle microtubule network is unknown. Here, we define a minimal CPC midzone enrichment module. We show that the maximal enrichment of CPC at antiparallel microtubule overlaps requires PRC1-crosslinked microtubules and the interaction of CPC with two mitotic kinesins, KIF4A and KIF20A. We find that the two motors exhibit a division of labor: KIF20A delivers CPC from non-overlapping microtubules, and KIF4A retains CPC at PRC1-crosslinked overlaps. Conditional depletion of KIF4A in mitotic cells reveals that it is required for CPC localization at the spindle midzone in anaphase. Taken together, our findings reveal how the collective activity of two kinesins enables navigation through the complex microtubule network of the spindle to organize kinase signaling at the cell center for cytokinesis.

Joanna Stefano, Lara E. Elcavage, Sue-Jean Hong et al.

ABSTRACT The miR-200a and miR-200b families control mouse ovulation and are essential for female fertility. The ZEB1 transcription factor is a conserved target of both families and has been implicated as a key player in female fertility at multiple levels. Using gene-edited mice that express a miR-200a/b-resistant form of Zeb1 , we found that derepression of Zeb1 in the female pituitary caused decreased production of luteinizing hormone and anovulatory infertility. These phenotypes were accompanied by widespread changes in pituitary gene expression characterized by decreased levels of ZEB1 targets, which include the miR-200a/b miRNAs, as expected from the miR-200a/b–ZEB1 double-negative feedback loop. Also observed were increased levels of mesenchymal genes, neuronal genes, and miR-200a/b targets. These results show that a double-negative feedback loop centered on the miRNA regulation of a single transcription factor can significantly influence the expression of thousands of genes and have dramatic phenotypic consequences.

Zhaoyu Li, X.Z. Shawn Xu

Tingjian Chen, Narupat Hongdilokkul, Zhixia Liu et al.

Gorana Pobric, Elizabeth Jefferies, Matthew A. Lambon Ralph

Bonnie L. Lyons, Linda L. Waterman

AbstractPersonnel performing surgery on mice commonly lack formal medical training and most training in mouse surgery focuses on the mechanical skills required for a procedure with less emphasis on perioperative techniques. Consequently, a basic concept that underpins successful surgery, aseptic technique, may not be fully understood or incorporated into the training process. This unit provides a framework in which to plan and carry out surgical procedures in mice using appropriate aseptic technique. Curr. Protoc. Mouse Biol. 2:263‐271 © 2012 by John Wiley & Sons, Inc.

Alan B. Stone

H. Schmidt, W. Westheide

Bernd Küppers

Michael C. O'Neill

Eva N. Nyutu, Víctor Carmona-Galindo, Maris Polanco

Most introductory biology laboratories are taught using direct instruction. An alternative to the direct instruction laboratory course is the Course-Based Undergraduate Research Experience (CURE). CURE courses have been reported to positively impact undergraduate students, increasing self-efficacy, enhancing science identity, improving preparation and persistence for STEM careers, and increasing inclusion of underrepresented minorities in undergraduate research. While there are several affective benefits of CUREs, our literature review reveals an absence of studies assessing pre-health students’ science identity, self-efficacy, and perceptions after participating in a community-engaged CURE laboratory. We found that students agreed that their community-engaged laboratory course had CURE design features, Discovery and Relevance had the highest rating. Overall, our results indicate that self-efficacy improved from the beginning to the end of the semester. Students in the community-engaged CURE showed gains in science identity. Understanding student affective domain is critical for improving student learning in gateway biology laboratory courses since they play very important roles in determining whether students can complete their degrees in the STEM fields. Future research should examine the relationships between self-efficacy, science identity, student perceptions of the community-engaged CURE laboratories, and gender, major, and race/ethnicity.

Manfred D. Laubichler

J. F. Crow

P. Morales-Otero, A. Pomales-Lebron

Bentley Glass

Bentley Glass

Eliot Stellar

W. C. Boyd

W. Gordon Whaley