Title

Induced nitric oxide synthesis is dependent on induced alternatively spliced CAT-2 encoding L-arginine transport in brain astrocytes.

Document Type

Article

Abstract

The inducible isoform II of nitric-oxide synthase (iNOS) was recently cloned from brain and identified in astroglial cells. Induced nitric oxide biosynthesis occurs in brain cells only if extracellular cerebrospinal fluid contains -arginine. This study demonstrates for the first time that induced iNOS activity is strictly dependent on concomitant induction of an alternatively spliced transcript of the cat-2 gene encoding high affinity -arginine transporter System y+ in cultured rat astrocytes. Inhibition profiles of radiolabeled -arginine and -leucine uptake identified the dominance of Na+-independent transport System y+ serving cationic amino acids, with insignificant activities of Systems y+L, bo,+, or Bo,+. A reverse transcription-polymerase chain reaction/sequencing/cloning strategy was used to identify a single 123-base nucleotide sequence coding the high affinity domain of alternatively spliced CAT-2 (not CAT-2a) in astrocytes activated by lipopolysaccharide/interferon-gamma. Using this sequence as a cDNA probe, it was determined that CAT-2 mRNA, iNOS mRNA, and System y+ activity were concomitantly and strongly induced in astrocytes. Constitutive CAT-1 mRNA was weakly present in neurons and astrocytes, was not inducible in either cell type, and contributed

Keywords

Alternative Splicing, Amino Acid Sequence, Animals, Arginine, Astrocytes, Base Sequence, Biological Transport, Brain, Carrier Proteins, Cell Membrane, Enzyme Induction, Gene Expression, Interferon-gamma, Lipopolysaccharides, Membrane Glycoproteins, Membrane Proteins, Molecular Sequence Data, Nitric Oxide, Nitric Oxide Synthase, RNA, Messenger, Rats, Rats, Inbred WKY, Receptors, Virus, Recombinant Proteins

Medical Subject Headings

Alternative Splicing; Amino Acid Sequence; Animals; Arginine; Astrocytes; Base Sequence; Biological Transport; Brain; Carrier Proteins; Cell Membrane; Enzyme Induction; Gene Expression; Interferon-gamma; Lipopolysaccharides; Membrane Glycoproteins; Membrane Proteins; Molecular Sequence Data; Nitric Oxide; Nitric Oxide Synthase; RNA, Messenger; Rats; Rats, Inbred WKY; Receptors, Virus; Recombinant Proteins

Publication Date

9-27-1996

Publication Title

The Journal of biological chemistry

ISSN

0021-9258

Volume

271

Issue

39

First Page

24017

Last Page

24022

PubMed ID

8798637

Digital Object Identifier (DOI)

10.1074/jbc.271.39.24017

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