cDNA cloning, genomic organization, and in vivo expression of rat N-syndecan.
The amino acid sequence of rat N-syndecan core protein was deduced from the cloned cDNA sequence. The sequence predicts a core protein of 442 amino acids with six structural domains: an NH2-terminal signal peptide, a membrane distal glycosaminoglycan attachment domain, a mucin homology domain, a membrane proximal glycosaminoglycan attachment domain, a single transmembrane domain, and a noncatalytic COOH-terminal cytoplasmic domain. Transfection of human 293 cells resulted in the expression of N-syndecan that was modified by heparan sulfate chain addition. Heparitinase digestion of the expressed proteoglycan produced a core protein that migrated on SDS-polyacrylamide gels at an apparent molecular weight of 120, 000, identical to N-syndecan synthesized by neonatal rat brain or Schwann cells. Rat genomic DNA coding for N-syndecan was isolated by hybridization screening. The rat N-syndecan gene is comprised of five exons. Each exon corresponds to a specific core protein structural domain, with the exception of the fifth exon, which contains the coding information for both the transmembrane and cytoplasmic domains as well as the 3'-untranslated region of the mRNA. The first intron is large, with a length of 22 kilobases. The expression of N-syndecan was investigated in late embryonic, neonatal, and adult rats by immunoblotting and Northern blotting analysis. Among the tissues and developmental stages studied, high levels of N-syndecan expression were restricted to the early postnatal nervous system. N-syndecan was expressed in all regions of the nervous system, including cortex, midbrain, spinal cord, and peripheral nerve. Immunohistochemical staining revealed high levels of N-syndecan expression in all brain regions and fiber tract areas.
Carey
D J
DJ
Sigfried and Janet Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania 19822, USA.
Conner
K
K
Asundi
V K
VK
O'Mahony
D J
DJ
Stahl
R C
RC
Showalter
L
L
Cizmeci-Smith
G
G
Hartman
J
J
Rothblum
L I
LI
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D002460:Cell Line; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005091:Exons; D015870:Gene Expression; D015698:Genomic Library; D006801:Humans; D007150:Immunohistochemistry; D007438:Introns; D007668:Kidney; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000737:chemistry / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D013116:Spinal Cord / Q000378:metabolism*; D053670:Syndecan-3; D014162:Transfection
D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D021382:Protein Sorting Signals; D011509:Proteoglycans; D011994:Recombinant Proteins; C508301:SDC3 protein, human; C508303:Sdc3 protein, rat; D053670:Syndecan-3