Expression and Characterization of Calcium Channel Alpha1 Subunits in Atrial Tissue

Cardiac tissue expresses two types of voltage-activated calcium current, a high voltage-activated (HVA) L-type and a low-voltage activated (LVA) T-type. The LVA calcium current is often associated with growth and nuclear division. In atrial tissue, the LVA calcium current demonstrates developmental regulation and is upregulated in response to Growth Hormone (GH) and insulin-like growth factor I (IGF-1). It is unknown the alpha1 subunits responsible for producing the LVA current. However, previous studies had hypothesized a correlation between the alpha1E subunit and the expression of the atrial LVA calcium current. The expression of alpha1E in atrial tissue was confirmed through the use of RT-PCR. Nine overlapping clones spanning the entire alpha1E coding region were identified in 4-week rat atrial tissue. The predominant isoform, alpha1E-7, was identified through analysis of the three major regions of diversity. Minor PCR products may indicate slight expression of the alpha1E-1, alpha1E-3 and alpha1E-5 isoforms. The expression of WE was localized to cardiomyocytes through the use of isolated atrial myocytes and in situ hybridization. Interestingly, atrial myocytes were found to express not only alpha1E but also two members of the CaV3 family of alpha1 subunits (alpha1G and alpha1H). The results suggest that the expression of alpha1E-7, isoform significantly contributes to the expression of the atrial LVA current. However, it still remains to be seen the role of alpha1G and alpha1H in the atrial LVA calcium current.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Molecular and Integrative Physiology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Mitchell, Jennifer Wiedenman

Contributors dc:contributor

• Best, Philip M.

• Biology, Cell

Language dc:language

eng

Identifier

(MiAaPQ)AAI9971140

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/87274