Biomedical subjects

W A Held

Publications and source records attributed to W A Held.

49 records · Page 3Linked to original sources

PubMed1979

Multiple genes coding for the androgen-regulated major urinary proteins of the mouse.

We have purified a cDNA fragment complementary to the mRNA coding for one of the major urinary proteins (MUPs) synthesized in the mouse liver. Using this cDNA as a hybridization probe, we have shown that the level of MUP mRNA is lower in the livers of females and castrated males than in those of males. The addition of testosterone to females and castrated males results in an increase in the concentration of the mRNA to levels found in males. There are approximately 15 gene per haploid genome coding for the MUPs; this allows a possible new interpretation of some of the genetic data concerning the regulation of levels of the different MUPs in the urine (Szoka and Paigen, 1978). Finally, we have shown that mouse MUP and rat alpha 2u-globulin mRNA share common sequences, but that there are surprising differences in gene number and regulation of the genes in these two closely related animals.

Alpha-Globulins↗

PubMed1978

Analysis of mRNA populations by cDNA.mRNA hybrid-mediated inhibition of cell-free protein synthesis.

Hybridization of mRNA to its corresponding cDNA was found to specifically inhibit translation of the mRNA in vitro. Using hybridization of globin cDNA to globin mRNA as a model system, we found that equivalent amounts of cDNA were required both for the saturation of the mRNA hybridization and for complete inhibition of globin synthesis. Also, the rate of inactivation of translation was identical to the rate of hybridization and followed the predicted kinetic form. This assay has been applied to the analysis of a set of abundant mRNAs in mouse liver. Hybridization of liver mRNA with total liver cDNA in slight excess to a low C(0)t value specifically inhibited translation of several major polypeptides. Melting of the hybrids prior to translation restored synthesis of these polypeptides. Moreover, we found that different liver mRNAs are inactivated with different kinetics; the results suggest that the mRNAs for the major urinary polypeptide and for albumin are the most abundant and second most abundant, respectively, in mouse liver. The general applications of this technique are discussed.

Albumins↗

PubMed1977

Importance of initiation factor preparations in the translation of reovirus and globin mRNAs lacking a 5'-terminal 7-methylguanosine.

Reovirus and globin mRNAs which lack a 5'-terminal 7-methylguanosine are translated in a fractionated cell-free protein-synthesizing system. Efficient translation occurs only at optimal concentrations of reticulocyte initiation factor preparations and does not occur at optimal concentrations of ascites initiation factor preparations or at suboptimal concentrations of reticulocyte initiation factor preparations. The translation of "uncapped" mRNA in vitro, therefore, appears to be related to the efficiency of initiation of protein synthesis. At optimal concentrations of reticulocyte initiation factors, mRNA containing a 5'-terminal 7-methylguanosine is preferentially translated in the presence of mRNA which lacks a "cap." These results indicate that the 5'-terminal 7-methylguanosine on mRNA has a facilitatory rather than obligatory role in translation.

Animals↗

PubMed1975

Escherichia coli 30 S ribosomal proteins uniquely required for assembly.

Two 30 S ribosomal proteins from Escherichia coli have been found to be uniquely required for assembly of 30 S ribosomal subunits. 30 S ribosomes were reconstituted in vitro from 16 S RNA and a mixture of purified 30 S ribosomal proteins (sigma Si). In the absence of S16, sigmaSi-S16 particles were slowly assembled wich had physical and functional properties similar to complete particles (sigmaSi). The results indicate that S16 affects the rate of 30 S ribosome assembly, but does not appear to be directly involved in any known ribosomal function. Particles assembled in the absence of S18 (sigmaSi-S18) had high activity in poly(U)-directed polyphenylalanine synthesis but lost considerable activity upon isolation or purification. The loss of activity could be attributed primarily to the loss of proteins S11 and S21. S18 appears to have a major role in the stabilization of ribosome structure, especially the binding of proteins S11 and S21, and does not appear to be directly required for activity in poly(U)-directed polyphenylalanine synthesis. However, it is possible that S18 has some functional role which is not required for polyphenylalanine synthesis.

Bacterial Proteins↗

PubMed1974