Expression of PTPRO in the interneurons of adult mouse olfactory bulb

Abstract

PTPRO is a receptor-type protein tyrosine phosphatase (PTP) with a single catalytic domain in its cytoplasmic region and multiple fibronectin type III-like domains in its extracellular region. In the chick, PTPRO mRNA has been shown to be particularly abundant in embryonic brain, and PTPRO is implicated in axon growth and guidance during embryonic development. However, the temporal and spatial expression of PTPRO protein in the mammalian CNS, particularly in the juvenile and adult mammalian brain, has not been evaluated in any detail. By immunohistofluorescence analysis with a monoclonal antibody to PTPRO, we show that PTPRO is widely expressed throughout the mouse brain from embryonic day 16 to postnatal day 1, while expression is largely confined to the olfactory bulb (OB) and olfactory tubercle in the adult brain. In the OB, PTPRO protein is expressed predominantly in the external plexiform layer, the granule cell layer, and the glomerular layer (GL). In these regions, expression of PTPRO is predominant in interneurons such as γ-aminobutyric acid (GABA)-ergic or calretinin (CR)-positive granule cells. In addition, PTPRO is expressed in GABAergic, CR-positive, tyrosine hydroxylase-positive, or neurocalcin-positive periglomerular cells in the GL. Costaining of PTPRO with other neuronal markers suggests that PTPRO is likely to be localized to the dendrites or dendritic spines of these olfactory interneurons. Thus, PTPRO might participate in regulation of dendritic morphology or synapse formation of interneurons in the adult mouse OB. INDEXING TERMSCNS; receptor-type tyrosine phosphatase; granule cells; periglomerular cells; localization; maturation Protein tyrosine phosphatases (PTPs) play important roles in the development and function of the central nervous system (CNS; Paul and Lombroso, 2003). Based on amino acid sequence and cellular localization, PTPs have been classified into two groups: the receptortype PTPs (RPTPs) and the nonreceptor type PTPs (Andersen et al., 2001;Alonso et al., 2004). RPTPs are further classified into eight subgroups (R1-R8 subtypes), largely according to the primary structures of their extracellular domains (Andersen et al., 2001 (Thomas et al., 1994;Tagawa et al., 1997;Tomemori et al., 2000). Indeed, five spliced isoforms of this PTP protein have been described (Beltran et al., 2003). Two transmembrane-type isoforms are highly expressed in the brain (Tagawa et al., 1997;Beltran et al., 2003) and podocytes of renal glomeruli Wharram et al., 2000), and three truncated isoforms (PTPϕ or PTPROt), which lack the extracellular domains, are expressed mainly in macrophages, B cells, or osteoclasts (Pixley et al., 1995;Wu et al., 1996;Aguiar et al., 1999). In the nervous system, PTPRO is implicated in axon growth and guidance during embryonic neurogenesis. In the chick brain, maximal expression of cPTPRO (previously named CRYP2), a chick homolog of mammalian PTPRO, was observed between embryonic day (E) 8 and E13, consistent with pervasive axon extension and tract formation in the ...

Tyrosine phosphorylation of R3 subtype receptor‐type protein tyrosine phosphatases and their complex formations with Grb2 or Fyn

“…Rat mAbs to mouse SAP-1, to mouse PTPRO or to mouse VE-PTP were generated and prepared as previously described (Kotani et al 2009;Sadakata et al 2009;Mori et al 2010). A mouse mAb to phosphotyrosine (4G10) was from Millipore (Billerica, MA, USA).…”

“…Expression vectors for mouse SAP-1, mouse VE-PTP and mouse PTPRO were generated as described (Kotani et al 2009;Sadakata et al 2009;Mori et al 2010). A full-length cDNA of mouse Grb2 was amplified by reverse transcriptionpolymerase chain reaction (RT-PCR) with total RNA from mouse brain (C57BL ⁄ 6) to construct an expression vector for Myc epitope-tagged Grb2.…”

Microglial peri‐somatic abutments classify two novel types of GABAergic neuron in the inferior colliculus

“…It does not bind to calretinin and pre-adsorption of diluted antiserum with calbindin removed all the labeling in human brain (Huynh et al, 2000). Previous labeling of mouse olfactory bulb (Kotani et al, 2010), rat piriform cortex (Gavrilovici et al, 2010) and guinea pig enteric nervous system (Liu et al, 2005) all showed highly selective cytoplasmic labeling of neurons. We observed labeling consistent with previous reports.…”