Investigating the role of novel gene -C20orf197.

The C20orf197 gene which is on chromosome 20 open reading frame 197, was sequenced at least 15 years ago, but even today, it still remains uncharacterised for the public. Meanwhile, over the last few decades it has become apparent that the incidence of acute promyelocytic leukaemia (APL) is increasing. APL is characterised by the accumulation of immature granulocytes, due to these cells being unexpectedly terminated at an early naive differentiation stage. C20orf197 is a novel discovery gene and we have found it has a great effect on granulocyte differentiation. Therefore C20orf197 is a good candidate for a potential novel therapeutic intervention in the treatment of myeloid leukaemia. The NB4 cell line has been used as a model for studies of APL and granulocyte differentiation in vitro. Though the mechanisms underlying APL/granulocyte differentiation have been studied for about three decades, a comprehensive picture of the molecular nature remains incomplete. After several hypotheses have been disproved as shown in supplementary chapter, in this dissertation, based on our own studies, we, in the world wide, for the first time elucidate the function of this novel C20orf197 gene and propose that this gene has an effect on granulocyte differentiation. We first collected and combined all the clues from human tissue, cell lines expression and structure prediction, then we established knockout C20orf197 NB4 cell lines and set up baseline transcriptional profiles of ATRA induced wild type NB4. Then we examined global transcriptional change in the NB4 knockout C20orf197 cell line before and after induction by ATRA. After validation of the transcriptional landscape by cytokines and expression of differentiation markers at single time point and different time points, we found C20orf197 was the contributor for granulocyte differentiation. Thus, our studies provide first-hand information in the world, about the biological role of the uncharacterised novel gene C20orf197 and C20orf197 dependent or independent processes