Poly(ADP-ribose) glycohydrolase and poly(ADP-ribose)-interacting protein Hrp38 regulate pattern formation during Drosophila eye development

Abstract

Drosophila Hrp38, a homolog of human hnRNP A1, has been shown to regulate splicing, but its function can be modified by poly(ADP-ribosyl)ation. Notwithstanding such findings, our understanding of the roles of poly(ADP-ribosyl)ated Hrp38 on development is limited. Here, we have demonstrated that Hrp38 is essential for fly eye development based on a rough-eye phenotype with disorganized ommatidia observed in adult escapers of the hrp38 mutant. We also observed that Poly(ADP-ribose) Glycohydrolase (Parg) loss-of-function, which caused increased Hrp38 poly(ADP-ribosyl)ation, also resulted in the rough-eye phenotype with disrupted ommatidial lattice and reduced number of photoreceptor cells. In addition, ectopic expression of DE-cadherin, which is required for retinal morphogenesis, fully rescued the rough-eye phenotype of the hrp38 mutant. Similarly, Parg mutant eye clones had decreased expression level of DE-cadherin with orientation defects, which is reminiscent of DE-cadherin mutant eye phenotype. Therefore, our results suggest that Hrp38 poly(ADP-ribosyl)ation controls eye pattern formation via regulation of DE-cadherin expression, a finding which has implications for understanding the pathogenic mechanisms of Hrp38-related Fragile X syndrome and PARP1-related retinal degeneration diseases.

ARTD1/PARP1 Negatively Regulates Glycolysis by Inhibiting Hexokinase 1 Independent of NAD + Depletion

“…The alignment of HK1 with bona fide PAR binding motifs from histones H2A, H2B, H3, H4B (known to encode very strong PBMs), XRCC1 (Pleschke et al, 2000), the mitochondrial protein AIF (Wang et al, 2011; Yu et al, 2006; Yu et al, 2002), the stress signalling protein DEK (Fahrer et al, 2010; Kappes et al, 2008), the experimentally validated PBM within hnRNP-A1 (Gagne et al, 2003; Ji et al, 2013; Ji and Tulin, 2009), and Werner syndrome protein (Popp et al, 2013), supports that HK1 encodes a PBM ( Fig. 6A ).…”

Poly(ADP-Ribosyl)ation of hnRNP A1 Protein Controls Translational Repression in Drosophila

“…The primary antibodies used were rabbit anti-Hrp38 (1:10,000) (18) and mouse anti-Hrp36 (P11; 1:500; a gift from H. Saumweber) (31). For the detection of the pADPr level, the cell lysates extracted from the control and Parg dsRNA-treated cells were immunoprecipitated with rabbit anti-pADPr antibody (Enzo) and probed with mouse anti-pADPr antibody (10H) (Calbiochem) as described before (19). Mouse antitubulin (E7; 1:1,000; DSHB) was used as the loading control.…”

“…Coimmunoprecipitation (co-IP) was used to detect the interaction between pADPr and Hrp38 in Drosophila S2 cells by a previously published method (19). Briefly, 1 ml of cells (0.5 ϫ 10 6 /ml) per well was treated with Parg dsRNA (15 g per well) for 5 days.…”

“…As the founding member of hnRNP proteins, Drosophila Hrb98DE/Hrp38 regulates splicing and translation of several genes during development (7,(18)(19)(20). In addition, posttranslational modification of Hrp38 by poly(ADP-ribosyl)ation results in the regulation of Hrp38-dependent pathways, such as splicing and translation (7,19,20).…”

“…In addition, posttranslational modification of Hrp38 by poly(ADP-ribosyl)ation results in the regulation of Hrp38-dependent pathways, such as splicing and translation (7,19,20). Recent studies have also suggested that mutations of hrp38, or its homolog hrp36, or their abnormal expression, cause several neurodegenerative diseases, such as fragile X syndrome (21,22), polyglutamine (poly-Q) disorders (23,24), and amyotrophic lateral sclerosis (ALS) (25,26).…”