A distinct mRNA encoding a soluble form of ICAM-1 molecule expressed in human tissues.
A soluble form of ICAM-1 (sICAM-1) have been observed in normal human serum (Rothlein et al., J. Immunol. 147, 3788-3793) and at elevated levels in inflammatory and tumor bearing status (Seth et al., Lancet, 338, 83-84; Giavazzi et al., Canc. Res. 52, 2628-2630; Harning et al., Canc. Res., 51, 5003-5005). However, the mechanism to produce the sICAM-1 has been still unknown. In this report we presented evidence for the presence of the mRNA specifically encoding sICAM-1, which is probably generated by alternative splice donor site selection. A 19-base deletion occurred right upstream of the transmembrane region gave rise to reading frameshift and eliminate the entire transmembrane and cytoplasmic domains, resulting in incapability of ICAM-1 molecules to reside in the membrane. A reverse transcription-polymerase chain reaction (RT-PCR) using a primer pair specific to sICAM-1 revealed a positive expression in all tissues analyzed, though the amount and the ratio to the conventional species varied slightly from tissue to tissue. Inflammatory cytokines displayed a complex pattern in the ICAM-1 mRNA expression depending on the combination of cytokines and the cultured cell lines used.
Wakatsuki
T
T
Department of Biochemistry II, National Defense Medical College, Saitama, Japan.
Kimura
K
K
Kimura
F
F
Shinomiya
N
N
Ohtsubo
M
M
Ishizawa
M
M
Yamamoto
M
M
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D016207:Cytokines / Q000494:pharmacology; D018965:Frameshifting, Ribosomal; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D009928:Organ Specificity; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D012995:Solubility
D016207:Cytokines; D012333:RNA, Messenger; D018799:Intercellular Adhesion Molecule-1