Biomedical subjects

G Ab

Publications and source records attributed to G Ab.

75 records · Page 5Linked to original sources

PubMed1970

Metabolism of ribosomal precursor ribonucleic acid in kidney.

The labile precursors of ribosomal RNA in mouse kidney are preserved when nuclei rapidly isolated after sieving through multiple screens are swollen and cleansed in the presence of an RNase inhibitor before digestion with DNase and phenol extraction. The kinetics of nucleolar labeling analyzed on polyacrylamide gels show that 36S RNA is the major intermediate product in the catabolism of the original 45S RNA precursor to 32S RNA, from which 28S RNA is derived. Each kidney nucleus contains about 200-600 molecules of 45S RNA; the turnover time of the 45S pool is about 3 +/- 2 min. Compared with HeLa cells, kidney nuclei have a different major intermediate product and a much smaller and more rapidly turning-over pool of ribosomal precursor RNA.

Animals↗

PubMedDate not supplied

Cloning and sequencing of the malate synthase gene from Hansenula polymorpha.

We have cloned the MAS gene, encoding the microbody matrix enzyme malate synthase (EC 4.1.3.2.) from the methylotrophic yeast Hansenula polymorpha. The gene was isolated by screening of a genomic library with a mixed-sequence probe, based on the partial amino acid sequence of the purified enzyme. The nucleotide sequence of a 2.4-kilobase stretch of DNA covering the MAS gene was determined. The gene contains an open reading frame of 555 amino acids, amounting to a calculated molecular mass of 63,254 for the encoded protein. Comparison of the amino acid sequence with the malate synthase sequences of Escherichia coli, Brassica napus L. and Cucumis sativus L. clearly establishes the homology of all four proteins. Compared to the soluble enzyme from E. coli, the malate synthases from H. polymorpha and both plant species, which are located in the microbodies, have a short carboxy-terminal extension. In the plant malate synthases, the extension is probably involved in routing to the microbodies, since it contains the potential peroxisomal targeting signal, Ser-Arg/Lys-Leu, at the carboxy terminus. The H. polymorpha enzyme terminates with similar amino acids, but their sequence, Ser-Leu-Lys, does not conform to any of the known peroxisomal targeting signals.

Amino Acid Sequence↗

PubMedDate not supplied

Hormonal control of vitellogenin synthesis in avian liver.

Estradiol induces the synthesis of vitellogenin in the avian liver. We describe the precursor-product relationship between vitellogenin and the yolk proteins phosvitin and lipovitellin. The high rate of vitellogenin synthesis is a consequence of the accumulation of a stable messenger RNA. We suggest that estradiol acts at the level of the genome by opening a hitherto non-transcribed gene.

Animals↗