Morphological Characterization of Transgenic Mice Hearts

Presenter Information

Jennifer Heibel, Minnesota State University, Mankato
Brandon Boeck, Minnesota State University, Mankato
Ashley Overby, Minnesota State University, Mankato

Location

CSU Ballroom

Start Date

9-4-2012 10:00 AM

End Date

9-4-2012 11:30 AM

Student's Major

Biological Sciences

Student's College

Science, Engineering and Technology

Mentor's Name

Marilyn Hart

Mentor's Department

Biological Sciences

Mentor's College

Science, Engineering and Technology

Second Mentor's Name

Michael Bentley

Second Mentor's Department

Biological Sciences

Second Mentor's College

Science, Engineering and Technology

Description

The heart is a specialized muscle found in all animals with a circulatory system that is responsible for pumping blood throughout blood vessels by rhythmic contractions. The vertebrate heart is composed of myofibrils which maintain a precise alignment of two major components, actin and myosin. The ends of actin filaments are attached to a structural anchor, the Z line that maintains the alignment of the thin filament. Biochemical and cell biological studies suggest that actin capping (CP) attaches one end of the actin filament to the Z line. In previous studies, mice with reduced expression of CP displayed major structural defects in muscle unit organization, leading to an enlarged heart and ensuing lethality. To determine the basis of the myofibril defect, we examined the hearts of transgenic and wildtype mice using scanning electron microscopy. The myocardium of both transgenic and wildtype mice were treated with 1% elastase/1% collagenase and fixed in 2.5% glutaraldehyde. The prepared tissue was freeze dried, sputter coated with gold, and visualized using a JEOL JSM 6510LV/LGS scanning electron microscope. Digital images were captured and analyzed for alterations in myofibril organization. In general, the genetically altered myocardium displayed filament disarray relative to their wild type counterparts.