Regulation of the expression of galactoside-binding lectin during human monocytic differentiation.
The widely distributed hL-31 (CBP35, epsilon BP, mL-34, L-29, Mac-2) is a Ca(2+)-independent galactoside-binding lectin which functions as a receptor on mammalian cells for glycoproteins containing poly-N-acetyllactosamine side chains. Little is known about the regulation of its expression. The human promyelocytic leukemia cell line, HL-60, was used to determine whether expression of hL-31 (Mac-2) correlated with macrophage/monocyte differentiation. Nondifferentiated HL-60 cells and HL-60 cells grown in the presence of 1.24 microM retinoic acid expressed only trace amounts of hL-31. In contrast, both hL-31 transcripts and protein were detected at 8 h after addition of 17 nM 12-O-tetradecanoylphorbol-13-acetate and reached maximal levels at 24 h. Addition of actinomycin D along with 12-O-tetradecanoylphorbol-13-acetate blocked accumulation of hL-31 mRNA. In contrast, addition of actinomycin D to 12-O-tetradecanoylphorbol-13-acetate-treated HL-60 cells that had already accumulated high levels of hL-31 mRNA did not cause significant reduction in RNA levels until 6-8 h had elapsed. Since increased hL-31 expression was not associated with an increase in transcriptional activity of the hL-31 gene, these results suggest that hL-31 expression is regulated at the posttranscriptional level, at least in part, by stabilization of its mRNA. The results also indicate that the processes leading to increased hL-31 expression in HL-60 cells may be specific to differentiation along the monocyte/macrophage pathway.
Nangia-Makker
P
P
Metastasis Research Program, Michigan Cancer Foundation, Detroit 48201.
Ochieng
J
J
Christman
J K
JK
Raz
A
A
D000199:Actins / Q000096:biosynthesis; D015152:Blotting, Northern; D015153:Blotting, Western; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D005697:Galactosides / Q000378:metabolism; D037161:Galectins; D015870:Gene Expression / Q000187:drug effects; D006388:Hemagglutinins / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute; D009000:Monocytes / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000199:Actins; D005697:Galactosides; D037161:Galectins; D006388:Hemagglutinins; D012333:RNA, Messenger; D003609:Dactinomycin; D014212:Tretinoin; D013755:Tetradecanoylphorbol Acetate