CLONING FROM A MOUSE OSTEOBLASTIC CELL-LINE OF A SET OF TRANSFORMING-GROWTH-FACTOR-BETA-1-REGULATED GENES, ONE OF WHICH SEEMS TO ENCODE A FOLLISTATIN-RELATED POLYPEPTIDE
M. Shibanuma et al., CLONING FROM A MOUSE OSTEOBLASTIC CELL-LINE OF A SET OF TRANSFORMING-GROWTH-FACTOR-BETA-1-REGULATED GENES, ONE OF WHICH SEEMS TO ENCODE A FOLLISTATIN-RELATED POLYPEPTIDE, European journal of biochemistry, 217(1), 1993, pp. 13-19
Transforming growth factor(TGF)beta1 is a potent inhibitor of growth i
n mouse osteoblastic MC3T3-E1 cells. To isolate genes that are induced
by TGFbeta1, the differential screening method was adopted using a cD
NA library constructed from cells treated with TGFbeta1 for 4 h. Six i
ndependent cDNA clones were isolated (TGFbeta-stimulated clone, TSC-5,
TSC-36, TSC-115, TSC-128, TSC-160 and TSC-161), the expression of whi
ch was increased by TGFbeta1-treatment with maximal expression at 6-10
h. The steady-state levels of TSC-36, TSC-128 and TSC-160 increased a
lmost tenfold, whereas those of TSC-5, TSC-115 and TSC-161 were elevat
ed at most threefold. From partial nucleotide sequences, TSC-160 was f
ound to be identical to rrg (ras-recision gene, lysyl oxydase), and TS
C-115 had 80% similarity with tropomyosin cDNA, whereas other genes se
emed novel. Expression of TSC-36 and TSC-160 was dramatically decrease
d in v-Ki-ras-transformed MC3T3 cells or in transformed NIH 3T3 cells
(DT), and was recovered to normal levels in a flat revertant (C11). A
nearly full-length copy of TSC-36 cDNA was isolated, and an open readi
ng frame indicated that it encodes a protein of 35 kDa. An antiserum w
as raised against the C-terminal peptide predicted from the nucleotide
sequence, and a polypeptide with an approximate molecular mass of 38
kDa was detected in cultured medium of MC3T3-E1 cells. The amino acid
sequence of TSC-36 protein was found to have some similarity with foll
istatin, an activin-binding protein, and a limited similarity with the
secreted protein rich in cysteine (SPARC).