A novel zinc finger gene, ZNF465, is inappropriately expressed in acute myeloid leukaemia cells.

Abstract

To increase our knowledge of leukaemia-associated antigens, especially in acute myeloid leukaemia (AML) M4, we prepared a phage display cDNA library using mRNA from the bone marrow cells of a patient with AML M4 at diagnosis. We immunoscreened 10(6) pfu with autologous sera and identified an antigen which we named GKT-AML8. The cDNA showed more than 99% similarity to a sequence on 2q21.2 and 95% sequence similarity to a sequence on 19q13.3. These genes were named ZNF465 and ZNF466, respectively, following HUGO Gene Nomenclature Committee (HGNC) guidelines. Expressed sequence tag data suggests that both genes are transcriptionally active. ZNF465 and ZNF466 encode a 5' krüppel associated box domain typical of negative regulators of gene transcription. We have confirmed the translational start site in the +1 frame in a near-Kozak sequence that produces a 102 amino acid polypeptide from ZNF465. The high level of sequence similarity between ZNF465 and ZNF466 makes their transcripts almost indistinguishable by real-time polymerase chain reaction (RT-PCR). However, GKT-AML8 showed most sequence similarity to ZNF465 and no transcript matching the 3' ZNF466 sequence could be detected in patient samples or healthy volunteers. ZNF465/466 expression was detectable in 12/13 AML and 10/14 chronic myeloid leukaemia patients' samples but not in normal donor peripheral blood (0/8) or 0/3 bone marrow samples which had been separated into CD34(+) and CD34(-) samples. The altered expression of ZNF465/466 in patients' samples and its absence in healthy donor haematopoietic samples indicate that ZNF465 is overexpressed in early myeloid disease and as such may represent a promising target for immunotherapy.