Anti-POLDIP2 (aa 129-143) polyclonal antibody

Osteoporosis is one of the most prevalent ageing-associated diseases that are soaring in the modernworld. Although various aspects of the disease have been investigated to understand the bases of osteoporosis, the pathophysiological mechanisms underlying bone loss is still incompletely understood. Poldip2 is a molecule that has been shown to be involved in cellmigration of vascular cells and angiogenesis. However, expression of Poldip2 and its regulation in bone cellswere not known. Therefore, we examined the Poldip2mRNAexpression and the effects of bone regulators on the Poldip2 expression in osteoblasts. We found that Poldip2 mRNA is expressed in osteoblastic MC3T3-E1 cells. As FGF controls osteoblasts and angiogenesis, FGF regulationwas investigated in these cells. FGF suppressed the expression of Poldip2 inMC3T3-E1 cells in a time dependent manner. Protein synthesis inhibitor but not transcription inhibitor reduced the FGF effects on Poldip2 gene expression in MC3T3-E1 cells. As for bone-related hormones, dexamethasone was found to enhance the expression of Poldip2 in osteoblastic MC3T3-E1 cells whereas FGF still suppressed such dexamethasone effects. With respect to function, knockdown of Poldip2 by siRNA suppressed themigration of MC3T3-E1 cells. Poldip2 was also expressed in the primary cultures of osteoblast-enriched cells and FGF also suppressed its expression. Finally, Poldip2 was expressed in femoral bone in vivo and its levels were increased in aged mice compared to young adult mice. These data indicate that Poldip2 is expressed in osteoblastic cells and is one of the targets of FGF. (C) 2016 Wiley Periodicals, Inc.

PDIP38 (polymerase delta interacting protein 38) was originally discovered as a protein that interacts with DNA polymerase and PCNA. PDIP38 is present in multiple intracellular locations and is a multifunctional protein that has been implicated in several diverse cellular functions. We investigated the nuclear localization of PDIP38 in order to gain insights to its response to UV damage. PDIP38 was found to form distinct nuclear foci in response to UV irradiation in several cell lines, including HeLa S3 and A549 cells. However, these foci were not those associated with UV repair foci. Using various markers for different nuclear subcompartments, the UV-induced PDIP38 foci were identified as spliceosomes/nuclear speckles, the storage and assembly sites for mRNA splicing factors. To assess the role of PDIP38 in the regulation of splicing events, the effects of PDIP38 depletion on the UV-induced alternate splicing of MDM2 transcripts were examined by nested RT-PCR. Alternatively spliced MDM2 products were induced by UV treatment but were greatly reduced in cells expressing shRNA targeting PDIP38. These findings indicate that upon UV-induced DNA damage, PDIP38 is translocated to spliceosomes and contributes to the UV-induced alternative splicing of MDM2 transcripts. Similar results were obtained when cells were subjected to transcriptional stresses with actinomycin D or -amanitin. Taken together, these studies show that PDIP38 is a protein regulated in a dynamic manner in response to genotoxic stress, as evidenced by its translocation to the spliceosomes. Moreover, PDIP38 is required for the induction of the alternative splicing of MDM2 in response to UV irradiation.