In this report we describe the use of recombinant retroviruses to characterize the activity of an exogenous promoter in primary cells obtained from patients with lymphoproliferative disorders. The infection of a variety of cultured and primary lymphoid cells with a recombinant retrovirus containing a histone promoter-driven beta-galactosidase gene is shown to result in the expression of beta-ga...

A previously constructed trp-S-lacZ fusion encoding a hybrid protein with beta-galactosidase activity was subcloned from a multicopy plasmid onto a lambda vector. Single-copy lysogens of lambda trpS-lacZ were used to determine whether trpS was regulated in a manner similar to that of other aminoacyl-tRNA synthetases. trpS regulation was found to resemble that of the majority of synthetases, in ...

In addition to information for current functions, the sequence of a gene includes potential information for the evolution of new functions. The wild-type ebgA (evolved beta-galactosidase) gene of Escherichia coli encodes a virtually inactive beta-galactosidase, but that gene has the potential to evolve sufficient activity to replace the lacZ gene for growth on the beta-galactoside sugars lactos...

We present the detection of single beta-galactosidase molecules from Escherichia coli (Ecbeta Gal) using deep UV laser-based fluorescence lifetime microscopy. The native fluorescence from intrinsic tryptophan emission has been observed after one-photon excitation at 266 nm. Applying the time-resolved single-photon counting method, we investigated the fluorescence lifetime distribution and the b...

On the basis of previous frequency determinations we could set up large numbers of cultures, each containing less than one competent precursor B cell specific for beta-galactosidase or for each of three idiotopes previously found on a monoclonal anti-beta-galactosidase antibody. Cultures were polyclonally activated by either lipopolysaccharide or Nocardia-delipidated cell mitogen. Each culture ...

To optimize conditions for retroviral-mediated transfer of a recombinant gene to hepatocytes, the pMNSM-Tk-lacZ vector, which we had constructed to express the bacterial beta-galactosidase gene, was transduced to rat hepatocytes under various conditions, and the expression of beta-galactosidase activity was examined by cytochemical staining. Compared to the hepatocytes of adult rats, those of n...

Inducible and constitutive beta-galactosidase formation and radioactive amino acid incorporation were measured in cells recovering from various treatments which inhibit protein synthesis in the cell. Undelayed beta-galactosidase formation was found in stringent auxotrophs recovering from amino acid starvation, in cells recovering from glycerol or potassium starvation, and in bacteria recovering...

The ability to program recombinant gene expression in cardiac myocytes in vivo holds promise for the treatment of many inherited and acquired cardiovascular diseases. In this report, we demonstrate that a recombinant beta-galactosidase gene under the control of the Rous sarcoma virus promoter can be introduced into and expressed in adult rat cardiac myocytes in vivo by the injection of purified...

During growth of streptomycin-dependent strains of Escherichia coli in the absence of streptomycin (deprived growth), both constitutive and inducible synthesis of beta-galactosidase were preferentially inhibited. A similar preferential inhibition of constitutive and derepressed synthesis of alkaline phosphatase was observed. Catabolite repression accounted for part, but not all, of the inhibiti...