Submit a Letter to the Editor for:
I Klein, K Ojamaa, A M Samarel, R Welikson, C Hong
J Clin Invest. 1992;
89(1):68
doi:10.1172/JCI115587
Abstract |
Full text
|
PDF
C
ardiac work is a major determinant of heart size and growth. Heterotopic cardiac isografts are hemodynamically unloaded and undergo atrophy. To determine the molecular changes that occur as a result of hemodynamic unloading, we have studied the rate of synthesis of total cardiac proteins and myosin heavy chain (MHC) and the expression of the myosin heavy chain gene as reflected in the messenger RNA levels for alpha- and beta-MHC isoforms. 72 h after transplantation there is a significant decrease in left ventricular size accompanied by a 27% decrease in the rate of total cardiac protein synthesis and a 53% decrease in the rate of myosin heavy chain synthesis. In contrast to isografts 14 d after transplantation which have a decrease in protein synthetic capacity, simultaneous measurements of 18S ribosomal RNA and myosin messenger RNA suggest that after 3 d the decrease in synthesis is due to a change in the efficiency of protein translation. While the working in situ heart expresses primarily alpha-MHC mRNA (97%) hemodynamic unloading leads to a 43% decrease in alpha-MHC mRNA concentration and the de novo expression of the beta-MHC mRNA. Total MHC mRNA (alpha plus beta) concentration analyzed by a quantitative S1 nuclease protection assay was similar in the two groups of hearts. Thus, in association with hemodynamic unloading there are changes in cardiac myosin heavy chain content as a result of both gene transcription and protein translation mechanisms.
Guidelines:
The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. All accepted letters will be posted on our website within one week of acceptance. The Editors reserve the right to edit any letter for length, content, and clarity. Authors of all accepted letters will be asked to preview any changes. Authors will be notified by e-mail if their letters were not accepted. As this is a final decision, no appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML, if you wish. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editor directly at editors@the-jci.org.
