Immunolocalization of Actin in Transgenic and Wildtype Murine Myocardium

Location

CSU North Ballroom

Start Date

25-4-2006 10:00 AM

End Date

25-4-2006 12:00 PM

Student's Major

Biological Sciences

Student's College

Science, Engineering and Technology

Mentor's Name

Marilyn C. Hart

Description

In myocardium, actin and myosin filaments are organized into repeating units of sarcomeres, the basic unit of muscle contraction. Actin Capping Protien (CP) binds to the barbed ends of the actin filament at the Z-line, directing and maintaining the proper organization of the thin filament in the sarcomere. CP is a heterodimer composed of an alpha (α) and a beta (β) subunit. Muscle cells contain two β subunit isoforms, β1 and β2. The β1 isoform is present at the Z line; the β2 isoform is found elsewhere, including cell-cell junctions such as intercalated discs and myotendinous junctions and at the cortical regions underlying the plasma membrane in general. In previous studies, transgenic mice were generated that replaced the β1 isoform of CP with the β2 isoform of CP using the cardiac-specific promoter of the α-myosin heavy chain (α-MyHC) gene. We hypothesized that a decrease in β1 expression will lead to a disorganized myofibrillar structure and that the disorganization will become increasingly severe as a function of murine age. Murine hearts were extracted, frozen in liquid nitrogen and rinsed with IX Phosphate Buffer Saline (PBS). Frozen sections were prepared using a cryomicrotome and collected on gelatin coated slides. The tissue sections were fixed in 0.1% paraformaldehyde in PBS, quenched with ethanolamine, permeabilized with methanol, and washed in PBS. The sections were probed with mouse anti-actin primary antibody and anti-mouse IgG rhodamine conjugated secondary antibody. Our results support our hypothesis. Immunofluorescence studies revealed an increasing disorganization as a function of murine age.

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Apr 25th, 10:00 AM Apr 25th, 12:00 PM

Immunolocalization of Actin in Transgenic and Wildtype Murine Myocardium

CSU North Ballroom

In myocardium, actin and myosin filaments are organized into repeating units of sarcomeres, the basic unit of muscle contraction. Actin Capping Protien (CP) binds to the barbed ends of the actin filament at the Z-line, directing and maintaining the proper organization of the thin filament in the sarcomere. CP is a heterodimer composed of an alpha (α) and a beta (β) subunit. Muscle cells contain two β subunit isoforms, β1 and β2. The β1 isoform is present at the Z line; the β2 isoform is found elsewhere, including cell-cell junctions such as intercalated discs and myotendinous junctions and at the cortical regions underlying the plasma membrane in general. In previous studies, transgenic mice were generated that replaced the β1 isoform of CP with the β2 isoform of CP using the cardiac-specific promoter of the α-myosin heavy chain (α-MyHC) gene. We hypothesized that a decrease in β1 expression will lead to a disorganized myofibrillar structure and that the disorganization will become increasingly severe as a function of murine age. Murine hearts were extracted, frozen in liquid nitrogen and rinsed with IX Phosphate Buffer Saline (PBS). Frozen sections were prepared using a cryomicrotome and collected on gelatin coated slides. The tissue sections were fixed in 0.1% paraformaldehyde in PBS, quenched with ethanolamine, permeabilized with methanol, and washed in PBS. The sections were probed with mouse anti-actin primary antibody and anti-mouse IgG rhodamine conjugated secondary antibody. Our results support our hypothesis. Immunofluorescence studies revealed an increasing disorganization as a function of murine age.

Recommended Citation

Davis, Jacob R. and Meghan Bohland. "Immunolocalization of Actin in Transgenic and Wildtype Murine Myocardium." Undergraduate Research Symposium, Mankato, MN, April 25, 2006.
https://cornerstone.lib.mnsu.edu/urs/2006/poster-session-E/9