Regulation of globin gene expression in human K562 cells by recombinant activin A

Normand L. Frigon, Li En Shao, Arlene L. Young, Lina Maderazo, John Yu*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

32 Scopus citations


Recent studies indicate that a purified protein, activin A, belongs to the transforming growth factor β(TGF-β) superfamily. Similar to TGF-β, activin A can have different biologic activities, depending on the target tissues. We used recombinant activin A to demonstrate a possible regulatory role of this protein in modulating human erythroid differentiation in the human erythroid cell line, K562. Using genomic probes containing the second exon of α, β, γ, and ε globins, relative abundance of various types of globin transcripts in untreated and activin-treated K562 cells was examined with S1 nuclease analysis. Despite considerable homology amongst various globin sequences, these globin probes were highly specific for their unique mRNA species in the analyses. It was shown that the abundance of specific globin probe fragments for γ and ε globins (209 nucleotides) as well as α (180 nucleotides), which were protected from S1 digestion, increased many fold in K562 cells treated with activin A. In contrast, there were no specific transcripts of β globin detected in either the control or activin-treated cells. The increases in the level of fetal and embryonic β-like and α globin transcripts also confirmed earlier studies of Northern and slot-blot analyses using globin cDNA as probes. In addition, nuclear run-off transcription assay using isolated nuclei indicated that most of the increase in the globin transcripts after activin treatment could be attributed to the stimulation of transcription rate for globin genes. Transient transfection assays also provide evidence that activin A significantly stimulated transcriptional activity of an ε globin promoter in K562, but not in the nonerythroid Chinese hamster ovary cells. Therefore, it was concluded that activin A exerts its effects on globin gene expression at the level of transcription in erythroid cells.

Original languageEnglish
Pages (from-to)765-772
Number of pages8
Issue number3
StatePublished - 01 02 1992
Externally publishedYes


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