Introduction Northern analysis of human tissues [12], whereas p38g is
Brain Research 887 2000 350–358 www.elsevier.com locate bres
Research report
Immunolocalization of p38 MAP kinase in mouse brain
a a ,
b c
Masumi Maruyama , Tatsuhiko Sudo , Yoshitoshi Kasuya , Takashi Shiga ,
d a
Bing-Ren Hu , Hiroyuki Osada
a
Antibiotics Laboratory , RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198 Japan
b
School of Medicine , Chiba University, Chiba, Japan
c
Institute of Basic Medical Sciences , University of Tsukuba, Tsukuba, Japan
d
Queen ’s Medical Center, Hawaii, USA
Accepted 3 October 2000
Abstract
p38 has been implicated to play a critical role in regulating apoptosis in PC12 and cerebellar granule cells, and is inactivated in cultured fetal neurons in response to insulin. Though p38 is activated in microglia after ischemia, the physiological functions of p38 in the brain
are not well understood. As a first step to elucidate the physiological functions of p38 in the central nervous system, we raised a polyclonal antibody against p38 and performed immunohistochemical examination to demonstrate the localization of p38 in mouse brain.
Strong p38 immunoreactivity was apparent in fiber bundles including the olfactory tract, anterior commissure, corpus callosum, cingulum, internal capsule, stria terminalis, fimbria and alveus hippocampi, fornix, stria medullaris, optic chiasm and optic tract. Although similar
regions were stained with both anti-p38 and anti-neurofilament antibodies, intense p38 immunoreactivity was often observed in myelin sheath-like structures but not in axons. This is the first demonstration of the localization of p38 in the central nervous system and provides
an anatomical basis for understanding physiological roles of p38.
2000 Elsevier Science B.V. All rights reserved.
Theme : Neurotransmitters, modulators, transporters and receptors
Topic : Signal transduction: gene expression
Keywords : p38 MAP kinase; Immunohistochemistry; Oligodendrocyte; Central nervous system
1. Introduction Northern analysis of human tissues [12], whereas p38g is
expressed only in skeletal muscle [16] and d has limited p38 was first identified as either an anti-inflammatory
expression in kidney and lung [13]. drug CSAID binding protein [15], a lipopolysaccharide
In vitro studies have suggested that p38 regulates gene LPS activated kinase [8] or a stress responsive kinase
expression by phosphorylating transcription factors, CRE- [21]. p38 is a member of mitogen-activated protein kinases
BP1 ATF2 [19], MEF2C [9], CHOP [25] and a transcrip- MAPK and is activated by dual phosphorylation of the
tional regulator, Max [27]. Meanwhile p38 phosphorylates conserved TGY motif [8,15,21]. p38 has been implicated
cellular kinases such as MAPKAPK2 3 [17,21], resulting to play roles in converting extracellular stresses to cellular
in hyperphosphorylation of HSP27 to modulate actin responses. Thus far, four members of p38 have been
dynamics [7]. Although the functional relevance and identified in the human. Among them, p38a and b have
significance in physiological conditions are not well under- been shown to be expressed relatively ubiquitously, by
stood, p38 may play a role in stress responses. More recently, p38 has been implicated to play a critical
role in regulating apoptosis in PC12 [26] and cerebellar granule cells [14] by its activation. Conversely, p38 is
inactivated in cultured fetal neurons in response to insulin
Corresponding author. Tel.: 181-48-467-9542; fax: 181-48-462-
[10]. Global forebrain ischemia results in apoptosis in
4669. E-mail address
: sudopostman.riken.go.jp T. Sudo.
hippocampal CA1 neurons and activation of p38 in
0006-8993 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 0 0 6 - 8 9 9 3 0 0 0 3 0 6 3 - 8
M . Maruyama et al. Brain Research 887 2000 350 –358
351
microglias [24]. Moreover analysis performed in ATF2 chased from CLEA Japan Inc. Under deep anesthesia with
null mice has indicated that ATF2 plays a critical role in an intraperitoneal injection of sodium pentobarbital, mice
the hippocampal CA3 [20]. These results suggest that p38 were perfused through the left cardiac ventricle with saline
may play a critical part in maintenance of central nervous followed by ice-cold 4 paraformaldehyde in 0.1 M
system CNS through the determination of survival and phosphate buffered saline PBS, pH 7.4. The brain was
or death in response to extracellular stimuli. then removed and immersion fixed in the same fixative for
Here we report the localization of p38 in the adult 12 h at 48C. For paraffin sections, the brain was dehydrated
mouse brain as a first step to understanding its physiologi- in graded ethanol, embedded in paraffin, and sectioned at 4
cal functions in the CNS. mm thickness. For cryostat sections, the brain was im-
mersed in the series of 5, 15 and 30 sucrose solutions in PBS for cryoprotection, frozen in Tissue Tek O.C.T.