Nuclear localization of Obox4 is dependent on its homeobox domain

Abstract

ObjectiveOocyte-specific homeobox 4 (Obox4) is preferentially expressed in oocytes and plays an important role in the completion of meiosis of oocytes. However, the Obox4 expression pattern has not been reported yet. In this study, we investigated the subcellular localization of Obox4 using a green fluorescent protein (GFP) fusion expression system.MethodsThree regions of Obox4 were divided and fused to the GFP expression vector. The partly deleted homeodomain (HD) regions of Obox4 were also fused to the GFP expression vector. The recombinant vectors were transfected into HEK-293T cells plated onto coated glass coverslips. The transfected cells were stained with 4',6-diamidino-2-phenylindol and photographed using a fluorescence microscope.ResultsMutants containing the HD region as well as full-length Obox4 were clearly localized to the nucleus. In contrast, the other mutants of either the N-terminal or C-terminal region without HD had impaired nuclear localization. We also found that the N-terminal and C-terminal of the Obox HD contributed to nuclear localization and the entire HD was necessary for nuclear localization of Obox4.ConclusionBased on the results of the present study, we demonstrated that the intact HD region of Obox4 is responsible for the nuclear localization of Obox4 protein in cells.

Associations among Sebox and Other MEGs and Its Effects on Early Embryogenesis

“…This finding suggests that Sebox is certainly a significant regulator of ZGA, but it is not critical or exclusive because the expression levels of 5 out of 13 genes were not affected. SEBOX contains a homeodomain and may thus act as a transcription factor [ 8 , 26 , 27 ]. Indeed, a transcriptional activity assay confirmed a reduction of embryonic transcriptional activity after Sebox RNAi knockdown.…”

Pioneer Transcription Factors: The First Domino in Zygotic Genome Activation

“…The Obox4 protein is divided into three distinct regions: the N-terminal region, the central homeodomain (HD) region and the C-terminal region. Using a green fluorescent protein (GFP) fusion expression system, Park et al revealed that intact HD region of Obox4 which harbors the presumptive DNA-binding motif essential for its transcription factor activity, may be responsible for the nuclear localization of Obox4 [ 40 ].…”