Rat clusterin isolated from primary Sertoli cell-enriched culture medium is sulfated glycoprotein-2 (SGP-2).
Clusterin, a glycoprotein originally isolated from ram rete testis fluid, is a dimer composed of monomers with non-identical NH2-terminal amino acid sequences. In view of its possible role in cell-cell interactions in the seminiferous epithelium, we sought to identify such a protein in the rat. Using the bioassay developed for the ovine protein, rat clusterin was purified to apparent homogeneity by HPLC from primary Sertoli cell-enriched culture media. This protein is also a heterodimer consisting of monomers of Mr 43,000 (alpha) and Mr 35,000 (beta). NH2-Terminal amino acid sequence analysis indicated that the alpha subunit has a sequence of NH2-SLMPLSHYGPLSFHNMFQPFFDMIHQAQQA and the beta subunit, NH2-EQEFSDNELQELSTQGSRYVNKEIQNAVQG. These two subunits show marked similarity with the corresponding subunits of ram clusterin isolated from rete testis fluid. Using an antibody against the alpha subunit of rat clusterin, a cDNA clone was isolated from a rat testicular lambda gt11 cDNA library. Analyses of the amino acid sequence derived from the isolated rat clusterin cDNA and of the NH2-terminal amino acid sequences indicate that rat clusterin is identical to a Sertoli cell glycoprotein previously designated sulfated glycoprotein-2.
Cheng
C Y
CY
Population Council, New York 10021.
Chen
C L
CL
Feng
Z M
ZM
Marshall
A
A
Bardin
C W
CW
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D051152:Clusterin; D003470:Culture Media; D004247:DNA / Q000302:isolation & purification; D006023:Glycoproteins / Q000235:genetics / Q000302:isolation & purification*; D008297:Male; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012333:RNA, Messenger / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D012708:Sertoli Cells / Q000032:analysis*
D051152:Clusterin; D003470:Culture Media; D006023:Glycoproteins; D018832:Molecular Chaperones; D012333:RNA, Messenger; D004247:DNA