Human cDNAs encoding elongation factor 1γ and the ribosomal protein L19

Cells from human monocytic leukemia cell line THPl (1) can be induced to differentiate into more mature monocytic/ macrophagic phenotype by retinoic acid (RA) (2). THP1-S cell line, one of the variant cell lines derived from THP1, is approximately 10 times more sensitive dtan the parent cell line (2). In an attempt to characterize the gene expression during the cell differentiation, we undertook cDNA cloning of mRNAs that are down-regulated in THP1-S cells by RA. A cDNA library was constructed from poly(A)+ RNA from THP1-S cells in the Okayama-Berg vector (3). By means of differenil hybridization, two cDNAs were obtained and characterized by nucleotide sequencing.