Differential Gene Expression Profiles in G 1 and S Phase Synchronized Jurkat T Cell Leukemia Cells: Investigation Using an Expressed Sequence Tag Analysis

Abstract

ABSTRACT

The expressed sequence tag (EST) strategy is a useful approach for describing gene diversity and identifying changes in expression patterns between different populations of cells. We constructed two directionally cloned cDNA libraries from human Jurkat T cell leukemia cells synchronized in either the G₁ or the S phase of the cell cycle. Sequence analysis of 3398 randomly selected clones from G₁ phase and 3428 randomly selected clones from S phase was carried out for the purpose of comparing gene expression profiles. EST sequencing identified 1728 distinct transcripts from the G₁ phase library and 1623 distinct transcripts from the S phase library. Approximately 13% of these transcripts appeared to be differentially expressed between the G1 and S phases of the cell cycle. Among the differentially expressed genes were alpha k-1 tubulin, alpha enolase, CDC p55, and ubiquitin. The human homologue of cyclin B2 is also differentially expressed in the G₁ phase vs the S phase of the cell cycle. Northern blot analysis of mRNA levels in cells from either the G₁ or S phase of the cell cycle correlated well with the quantitation of mRNA from EST profile analysis.