Introduction

StructureN-terminal domainContaining different numbers of zinc fingers.Exhibit DNA binding activity when it has 3 or more zinc fingers.Bind to DNA sites contain the core motif GGGA and ZNFs 2,3

C -terminal domainOligomerization domain.Containing a bipartite transactivation domain and 2 zinc finger motifs. Mediate hommo or hetrodimerisation between isoforms and iteract in with other molecules.

Isoforms

ikaros gene expression in human non-lymphoid leukemia cell line

Different roles

Disease associated with ikaros

Function of Ikaros

Ikaros appears function both as a transcriptional repressor and as an activator through its ability to bind a large number of nuclear factors:

Histon deacetylase repressor complexses SIN3 ,NURD(causes gene inactivation)

ATP-dependent chromatin remodeling complexes SW1/SNF (can distrupt histon-DNA –complexes)

• TdT gene is initially down-regulated when ikaros dislocates the transcriptional activator Ets-1 from the TdT promotor.

• Down-regulation enhanced by an ikaros –dependent hetrochromatin formation at the TdT locus.

• Ikaros can keep the gene in an inactive state through recruitment of NURD.