Identification of a nervous tissue-specific chondroitin sulfate proteoglycan, neurocan, in developing rat retina.
OBJECTIVE
To identify the expression of neurocan, a nervous tissue-specific chondroitin sulfate proteoglycan, in retina and to elucidate its changes during development.


METHODS
Expressional changes of neurocan mRNAs in developing rat retinas were investigated by a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The localization and characterization of neurocan core proteins were also investigated with the use of Western blot analysis and immunohistochemistry.


RESULTS
Gene expression of neurocan was identified in retinas by RT-PCR. Semiquantitative analysis using Southern blot analysis revealed that mRNA expression for neurocan increased at increasing postnatal stages and that it reached its peak around postnatal day 7 (P7). Immunohistochemical studies demonstrated that in differentiating rat retinal (neuroblast) cells weak neurocan immunoreactivities were observed throughout the retina on embryonal days 14 (E14) and E16. During the early postnatal period, the immunoreactivities became most conspicuous in the inner and outer plexiform layers on P7 through P14. In adult retinas, only faint immunostaining was detected. Immunoblot analysis showed two positive bands of 220- and 150-kDa core glycoproteins after treatment with chondroitinase ABC. Further immunoblot analysis revealed that the expression of these two immunolabeled variants was regulated differently during retinal development.


CONCLUSIONS
The temporal and spatial regulation of expression of neurocan and its proteolytic variant during retinal development suggest that it may play a role in differentiation and neural network formation.
Inatani
M
M
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Japan.
Tanihara
H
H
Oohira
A
A
Honjo
M
M
Honda
Y
Y
D000818:Animals; D015139:Blotting, Southern; D015153:Blotting, Western; D019765:Chondroitin ABC Lyase / Q000494:pharmacology; D011508:Chondroitin Sulfate Proteoglycans / Q000032:analysis* / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D037181:Lectins, C-Type; D009417:Nerve Tissue / Q000737:chemistry / Q000187:drug effects / Q000196:embryology / Q000254:growth & development; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000235:genetics; D058580:Neurocan; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000737:chemistry* / Q000187:drug effects / Q000196:embryology* / Q000254:growth & development; D020133:Reverse Transcriptase Polymerase Chain Reaction
D011508:Chondroitin Sulfate Proteoglycans; D017931:DNA Primers; D037181:Lectins, C-Type; D009419:Nerve Tissue Proteins; D058580:Neurocan; D012333:RNA, Messenger; C076817:NCAN protein, human; D019765:Chondroitin ABC Lyase