Volume 4 Issue 1, June 1994: 1-7
ORIGINAL ARTICLES
Identification of an kB-like motif at the 5' upstream region of human lymphotoxin gene
Xu Rener, ShouYuan Zhao
Institute of Genetics, Fudan University, Shanghai 200433, China
Correspondence: Xu Rener
Lymphotoxin(LT) is a glycoprotein secreted by activated T cell. The expression of LT gene is mainly regulated at the level of transcription. By using human LT DNA as a probe, we carried out a RNA dot blotting test and found that the longer the time of Jurkat human Tlymphoma cells exposed to the PMA and PHA, the more endogenous LT mRNA could be produced. Results of gel retardation assay showed that the nuclear extract from Jurkat cells treated with PMA and PHA formed different DNA-protein complexes. Changes in complex patterns were observed at various time intervals of PMA and PHA induction. A specific protein-binding site was mapped out to be a 22-bp sequence at the 5'upstream regioll of human LT gene by DNase I footprinting analysis. This region was similar to the sequence recognized by the proteins of NFｋB family The results of fragment competition and homology analysis indicated that the 22-bp sequence contains a ｋB-like motif only which is located at the base pairs -100 to -90 (5'-GGGGGCTTCCC-3'). Thus, the NF-KB-like factors were involved in the protein-DNA interaction.Furthermore, there were more than one retardation assay. It suggested that there may be several NF-KB-like factors involvedin the regulation of LT gene transcription at the same site.
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