# Mechanics of Microtubule Aster Growth and Positioning

> **NIH NIH R01** · UNIVERSITY OF WYOMING · 2022 · $268,636

## Abstract

PROJECT SUMMARY/ABSTRACT
The microtubule cytoskeleton is critical for organization the insides of cells. At times during the
cell cycle, this network adopts the form of an astral array with microtubule fibers emanating from
a central focus and branching outward throughout the cell. Importantly, the center of this array is
typically found near the geometric center of the cell where it is anchored to the surface of the
nucleus. Forces generated by the microtubules themselves move the internal organs of the cell
during interphase, and because the network also serves as a scaffold upon which these organs
attach, its position dictates their spatial arrangement within the cell. During mitosis similar forces
positioning the cell division machinery and establish the eventual location of the cell division
plane.
Though aster centering is likely critical in all cells, it is particularly relevant in large cells
immediately after fertilization. Here, the male pronucleus (from the sperm) must transverse large
distances to reach the cell center and establish the location of mitotic spindle formation and
division plane positioning during the subsequent mitosis. Thus, errors in this process can lead to
erroneous cell division and have deleterious effects on development. Precisely how the
microtubule aster generates and responds to forces to move to the cell center remains
unanswered. In this work, we describe the application and continued development of a new
approach engineered to overcome existing limitations inherent to other approaches used to study
aster positioning. This approach relies on the use of photo-labile hydrogels, which can be
polymerized and degraded in response to exposure to specific wavelengths of light. When
combined with cell-free cytoplasmic extracts, it provides exquisite control of cytoplasmic shape
and volume in a platform that is amenable to visualization using standard wide-field and confocal
light microscopy.

## Key facts

- **NIH application ID:** 10456883
- **Project number:** 5R01GM135568-03
- **Recipient organization:** UNIVERSITY OF WYOMING
- **Principal Investigator:** JESSE C GATLIN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $268,636
- **Award type:** 5
- **Project period:** 2020-09-04 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10456883

## Citation

> US National Institutes of Health, RePORTER application 10456883, Mechanics of Microtubule Aster Growth and Positioning (5R01GM135568-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10456883. Licensed CC0.

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