Two subjects, of 11,000 healthy individuals screened, were found to be missing three and four immunoglobulin isotypes, respectively (IgA1, IgG2, and IgG4; IgA1, IgG2, IgG4, and IgE), and have been analyzed at the DNA level by means of Southern blotting and Ig heavy-chain-specific probes. A broad deletion within the heavy-chain constant region (C) gene cluster was found on chromosome 14 of both ...

The clathrin heavy chain is a major component of clathrin-coated vesicles that function in selective membrane traffic in eukaryotic cells. We disrupted the clathrin heavy chain gene (chcA) in Dictyostelium discoideum to generate a stable clathrin heavy chain-deficient cell line. Measurement of pinocytosis in the clathrin-minus mutant revealed a four-to five-fold deficiency in the internalizatio...

Heavy chain diseases are a family of rare, systemic syndromes typically associated with or representing a variant of a B-cell neoplasm. Their characteristic feature is production of a mutated immunoglobulin heavy chain incapable of either partnering with light chains in the formation of a full immunoglobulin molecule or of being degraded by the proteasome. The abnormal heavy chain is detected i...

To begin to understand the nature of myosin subunit assembly, we determined the region of a vertebrate sarcomeric myosin heavy chain required for binding of light chain 1. We coexpressed in Escherichia coli segments of the rat alpha cardiac myosin heavy chain which spanned the carboxyl terminus of subfragment 1 and the amino terminus of subfragment 2 with a full-length rat cardiac myosin light ...

Cells of the 315LV-1 (derived from NP1) variant line of MOPC 315 contain approximately 1% the normal intracellular level of the heavy (alpha) chain of IgA and no detectable light (lambda2) chain. The synthesis rate of alpha-chain in the variant, however, is similar to that in cells of the parent line. Moreover the relative amount of translatable alpha-chain mRNA that can be extracted from 315LV...

We have altered the spontaneous contractile activity of neonatal cardiac myocytes in culture to investigate the re-lationship between mechanical forces, myofibril assembly, and the localization and translation of (alpha)-myosin heavy chain mRNA. Immunofluorescence and in situ hybridization techniques revealed that contracting myocytes display well aligned myofibrils and a diffuse distribution o...

We have isolated a myeloma genomic DNA clone containing the variable and constant regions of a mouse alpha chain. Restriction enzyme analyses and electron microscopic R loop mapping have demonstrated that the variable region is separated from the constant region by 6.8 kilobases of intervening DNA. In addition, two intervening DNA sequences of 100--200 bases separate the constant region into th...

Transitions in cardiac myosin isotypes occur in response to a variety of stimuli. These are well documented in small, but less so in larger, mammals where data on quantitative isotype composition of normal atria and ventricles are scarce. In this study, heavy and light chain isotypes were examined in fetal, neonatal, and adult bovine and human hearts. Defined anatomical areas of chambers were s...

The expression and function of embryonic myosin heavy chain (eMYH) has not been investigated within the early developing heart. This is despite the knowledge that other structural proteins, such as alpha and beta myosin heavy chains and cardiac alpha actin, play crucial roles in atrial septal development and cardiac function. Most cases of atrial septal defects and cardiomyopathy are not associ...