Expression and characterization of the IPM 150 gene (IMPG1) product, a novel human photoreceptor cell-associated chondroitin-sulfate proteoglycan.
The interphotoreceptor matrix (IPM) occupies the extracellular space between the apical surface of the retinal pigmented epithelium and the external limiting membrane of the neural retina. This space contains two chondroitin sulfate proteoglycans, designated IPM 150 and IPM 200, which are likely to effect retinal adhesion and photoreceptor survival. In an effort to characterize human IPM 150, several cDNA clones encoding its core protein have been isolated from a human retinal cDNA library. Translation of overlapping cDNA sequences yields a novel core protein with a predicted molecular mass of 89.3 kDa. Northern and dot-blot analyses as well as the isolation of expressed sequence tags demonstrate that IPM 150 mRNA is expressed not only in the neural retina but also in several other non-ocular tissues. In situ hybridization analyses indicate that, in the eye, IPM 150 mRNA is expressed specifically by cone and rod photoreceptor cells. Characterization of IPM 150 proteoglycan core protein and identification of its site of synthesis are important steps towards understanding the architecture and biology of the IPM.
Kuehn
M H
MH
Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa 52240, USA.
Hageman
G S
GS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D011508:Chondroitin Sulfate Proteoglycans / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D005136:Eye Proteins; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D017403:In Situ Hybridization; D008252:Macaca fascicularis; D008969:Molecular Sequence Data; D020419:Photoreceptor Cells, Vertebrate / Q000378:metabolism*; D011509:Proteoglycans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D011508:Chondroitin Sulfate Proteoglycans; D017931:DNA Primers; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D005136:Eye Proteins; D006023:Glycoproteins; C486428:IMPG1 protein, human; D011509:Proteoglycans; D012333:RNA, Messenger