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N Hay

Publications and source records attributed to N Hay.

60 records · Page 4Linked to original sources
PubMed1982

Site of premature termination of late transcription of simian virus 40 DNA: enhancement by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole.

Sedimentation analysis of pulse-labeled RNA synthesized in nuclei isolated from simian virus 40-infected cells revealed an abundance of short cellular and viral RNAs. The relative amount of the short chains is increased in nuclei isolated from cells treated with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). The short viral RNAs were purified by hybridization to and elution from simian virus 40 DNA on filters, and their sizes were determined by gel electrophoresis. A major band of 93- to 95-nucleotide-long RNA was observed along with additional minor bands. Identical bands were revealed when the viral RNA was purified from nuclei of cells pretreated with DRB. The major band was identified as an aborted transcript of a RNA that initiated at the major initiation site (nucleotide 243). We have found that the DNA region where the RNA stops is A+T rich and is immediately preceded by a G+C-rich region that exhibits dyad symmetry, resembling the termination signal in prokaryotes. These observations show that RNA polymerase II responds to the same termination signal as the prokaryotic enzyme and suggest that a mechanism of attenuation regulates simian virus 40 late transcription.

DNA, Viral↗
PubMedDate not supplied

Distribution of mouse sulfated glycoprotein-1 (prosaposin) in the testis and other tissues.

Mouse sulfated glycoprotein-1 (SGP-1) is the homologue of rat SGP-1 and human prosaposin. Rat SGP-1 is one of the major secretory products of rat Sertoli cells in culture. Human prosaposin is the precursor of four lysosomal saposins, termed A, B, C, and D, that are generated by limited proteolysis. Saposins are sphingolipid-binding proteins that function as activators for lysosomal enzymes involved in sphingolipid hydrolysis of the former. Recently, we have generated a cDNA encoding the mouse SGP-1 by polymerase chain reaction amplification of a mouse testicular Uni-Zap XR cDNA library with two synthetic oligonucleotide primers and have used it as a probe for examining the tissue distribution of SGP-1 mRNA. We have also studied the distribution of the translation product of SGP-1 mRNA in the same tissues. The analysis demonstrated that SGP-1 is expressed ubiquitously in all tissues examined. This investigation showed that, in mouse testis, two forms of SGP-1 exist: a 70-kDa secreted protein and a 65-kDa protein corresponding to the lysosomal form of SGP-1, which may be involved in the generation of saposins. Light microscope immunocytochemistry with anti-SGP-1 antibody demonstrated that, in the mouse seminiferous tubules, the translation product of SGP-1 mRNA is expressed in Sertoli cells but not in germinal cells. Electron microscope immunogold labeling with anti-SGP-1 antibody yielded a strong reaction on lysosomes and phagolysosomes containing residual bodies but not on endosomes or luminal residual bodies. These results demonstrate that SGP-1 is not internalized from the lumen but is targeted directly to the lysosomes from the Golgi apparatus. Immunoblotting also confirmed the existence of a secreted form of testicular SGP-1 delivered to the lumen of the seminiferous tubules. The production of a secreted and a lysosomal form of SGP-1 by Sertoli cells indicates that this protein plays a multifunctional role. This study also suggests that the lysosomal form of SGP-1 may be involved in the degradation of membrane glycolipids from residual bodies phagocytosed by Sertoli cells.

Animals↗