Related Experiment Video

Updated: Aug 7, 2026

High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry
13:13

High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry

Published on: September 23, 2014

Role of homeodomain-only protein in the cardiac conduction system

Fang Liu1, Fraz A Ismat, Vickas V Patel

  • 1Cardiovascular Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.

Trends in Cardiovascular Medicine
|July 15, 2006
PubMed

Insights

A novel protein, Hop, is crucial for maintaining the cardiac conduction system (CCS) in mice. Its disruption causes conduction defects, suggesting Hop as a potential therapeutic target for heart conditions.

Area of Science:

  • Cardiology
  • Molecular Biology
  • Genetics

Background:

  • Cardiac conduction system (CCS) diseases pose significant challenges in adult patients, with limited non-device-based therapeutic options.
  • Transcription factors regulating CCS development and maintenance are emerging as potential therapeutic targets for degenerative diseases.
  • A small homeodomain-only protein (Hop) has been identified as critical for cardiac development and is highly expressed in the adult murine CCS.

Purpose of the Study:

  • To investigate the role of the homeodomain-only protein (Hop) in the adult cardiac conduction system (CCS).
  • To determine the effects of targeted Hop gene disruption on CCS structure and function in a murine model.

Main Methods:

  • Utilized a murine model with targeted disruption of the Hop gene locus.
  • Assessed cardiac conduction system morphology and connexin40 expression in wild-type and Hop-deficient mice.

Main Results:

  • Targeted disruption of Hop resulted in infra-nodal conduction defects in mice.
  • Connexin40 expression was downregulated within the CCS of Hop-deficient mice.
  • Loss of Hop did not significantly alter the size or distribution of the mature murine CCS.

Conclusions:

  • Hop plays a critical role in maintaining normal cardiac conduction and connexin40 expression in the adult murine CCS.
  • Hop disruption leads to conduction abnormalities, highlighting its potential as a therapeutic target for CCS diseases.
  • Further research is needed to ascertain Hop's association with human conduction system diseases.

More Related Videos

Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection08:52

Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection

Published on: February 17, 2015

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes12:49

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

Published on: September 24, 2013

Related Concept Videos

Conduction System of the Heart01:20

Conduction System of the Heart

The cardiac conduction system produces and transmits electrical impulses that prompt myocardial contraction, ensuring efficient heart function. This intricate system ensures that the heart beats in a coordinated and efficient manner, beginning with the atria and then the ventricles. The conduction system optimizes cardiac output by maintaining this precise sequence, which is crucial for adequate blood circulation.
This system relies on the unique properties of nodal and Purkinje cells:...
Conduction System of the Heart01:19

Conduction System of the Heart

Autorhythmicity is a term that refers to the heart's inherent ability to generate electrical signals and instigate muscle contractions. This self-regulating conduction system within the heart consists of two key components: the pacemaker cells and specialized conducting cells.
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
Electrophysiology of Normal Cardiac Rhythm01:19

Electrophysiology of Normal Cardiac Rhythm

The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
Cardiac Action Potential01:30

Cardiac Action Potential

Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Specialized Characteristics of Cardiac Muscles01:27

Specialized Characteristics of Cardiac Muscles

The primary role of cardiac muscles is to propel blood throughout the cardiovascular system. The cardiac muscle cells, or cardiomyocytes, exhibit specialized characteristics that allow them to perform this function.
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Structure of Cardiac Muscles01:13

Structure of Cardiac Muscles

Cardiac muscle, or myocardium, is a specialized type of muscle found exclusively in the heart. Its unique structural and functional characteristics enable the heart to perform its vital role of pumping blood throughout the body continuously and rhythmically. The cardiac muscle cells, or cardiomyocytes, possess an endomysium and perimysium but do not have an epimysium.
Compared to skeletal muscles, cardiac muscle cells are small and mostly have a single nucleus. Additionally, they are usually...