Differential expression of nm23 genes in adult mouse dorsal root ganglia.
Nm23 has been identified as a gene family encoding different isoforms of nucleoside diphosphate kinase (NDPK). This protein is a key enzyme in nucleotide metabolism and has been shown to play important roles in various cellular functions. In the present study, we have investigated the expression of three isotypes in mouse dorsal root ganglia. In situ hybridization and reverse transcriptase-polymerase chain reaction analysis demonstrated high levels of nm23-M1, -M2, and -M3 mRNA expression in peripheral nervous tissue. Moreover, in situ hybridization also displayed a specific nuclear localization for nm23-M2 mRNA. Immunohistochemistry with light and electron microscopy on isoform-specific antibodies revealed a differential subcellular distribution of NDPK isoforms. Isoform A was mainly cytosolic, showing only partial association with organelles. In contrast, isoform B was also found in the nucleus, which is in agreement with its proposed role as a transcription factor. The results also indicate a preferential association of isoform C with endoplasmic reticulum and plasma membranes in neuronal cells. Furthermore, isoform C appeared to combine with other NDPK isoforms as demonstrated by double-labeling evidence by electron microscopy and might be responsible for binding NDPK oligomers to membranes. Thus, isoform C may be considered as a protein of importance for maintaining intracellular pools of GTP in the vicinity of membranes and, hence, for transmembrane signaling. The results indicate a high expression of NDPK isoforms, not only in the central but also in the peripheral nervous system. Their different subcellular compartmentalization suggests that they have isoform-specific roles in neuronal cell physiology.
Barraud
Perrine
P
EA DRED 483, Laboratoire de Biologie de la Différenciation et du Développement, Université Victor Ségalen, 33 076 Bordeaux Cedex, France.
Amrein
Lilian
L
Dobremez
Eric
E
Dabernat
Sandrine
S
Masse
Karine
K
Larou
Monique
M
Daniel
Jean-Yves
JY
Landry
Marc
M
D000818:Animals; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D005727:Ganglia, Spinal / Q000502:physiology* / Q000648:ultrastructure; D015870:Gene Expression; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D054778:NM23 Nucleoside Diphosphate Kinases; D009701:Nucleoside-Diphosphate Kinase; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D054778:NM23 Nucleoside Diphosphate Kinases; D014157:Transcription Factors; C517939:Nme1 protein, mouse; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins