N-Terminally extended human ubiquitin-conjugating enzymes (E2s) mediate the ubiquitination of RING-finger proteins, ARA54 and RNF8

Spermatogenesis involves a series of cellular transformations and thousands of regulated genes. Previously, we showed that the triploid fish (3nBY) cannot produce mature spermatozoa. In the present study, evaluation of the testis microstructure revealed that germ cells of 3nBY could develop into round spermatids, but then degenerated, resulting in male infertility. In this study we comparatively analysed the testis transcriptomes from 3nBY and its diploid parent YB and identified a series of differentially expressed genes (DEGs) that were enriched in the Wnt signalling pathway and the apoptotic and ubiquitin-mediated proteolysis processes in 3nBY. Gene ontology functional analyses revealed that some DEGs in 3nBY were directly associated with the process of gamete generation, development and sperm flagellum assembly. In addition, the expression of a number of genes related to meiosis (Inhibitor Of DNA Binding 2 (ID2), Ovo Like Transcriptional Repressor 1 (OVOL1)), mitochondria (ATP1b (ATPase Na+/K+ Transporting Subunit Beta 1), ATP2a (ATPase, Ca++ Transporting, Cardiac Muscle, Slow Twitch 2), ATP5a (ATP Synthase F1 Subunit Alpha), Mitochondrially Encoded Cytochrome C Oxidase I (COX1), NADH Dehydrogenase Subunit 4 (ND4)) and chromatin structure (Histone 1 (H1), Histone 2a (H2A), Histone 2b (H2B), Histone 3 (H3), Histone 4 (H4)) was lower in the testes of 3nBY, whereas the expression of genes encoding ubiquitin (Ubiquitin Conjugating Enzymes (UBEs), Ring Finger Proteins (RNFs)) and apoptosis (CASPs (Caspase 3, Caspase 7,Caspase 8), BCLs (B-Cell Lymphoma 3, B-Cell CLL/Lymphoma 2, B Cell CLL/Lymphoma 10)) proteins involved in spermatid degeneration was higher. These data suggest that the disrupted expression of genes associated with spermatogenesis and the increased expression of mitochondrial ubiquitin, which initiates cell apoptosis, may result in spermatid degeneration in male 3nBY. This study provides information regarding the potential molecular regulatory mechanisms underlying male infertility in polyploid fish.

Download Full-text

Abstract 4965: Multiple ubiquitin-conjugating enzymes modulate the ubiquitination and downregulation of the EGFR by the Cbl RING finger ubiquitin ligase

10.1158/1538-7445.am2015-4965 ◽

2015 ◽

Author(s):

Ke Ma ◽

Philip Ryan ◽

Rachel Klevit ◽

Stanley Lipkowitz

Keyword(s):

Ubiquitin Ligase ◽

Ring Finger ◽

Conjugating Enzymes ◽

Ubiquitin Conjugating Enzymes

Download Full-text

Ubiquitin Ligase Activities of Bombyx mori Nucleopolyhedrovirus RING Finger Proteins

Journal of Virology ◽

10.1128/jvi.77.2.923-930.2003 ◽

2003 ◽

Vol 77 (2) ◽

pp. 923-930 ◽

Cited By ~ 56

Author(s):

Noriko Imai ◽

Noriyuki Matsuda ◽

Keiji Tanaka ◽

Akihiko Nakano ◽

Shogo Matsumoto ◽

...

Keyword(s):

Bombyx Mori ◽

Ubiquitin Ligase ◽

Mutational Analysis ◽

Ring Finger ◽

Zinc Ion ◽

Ubiquitin Ligase E3 ◽

Reticulocyte Lysates ◽

Ring Finger Proteins ◽

Ubiquitin Conjugating Enzymes

ABSTRACT The genome of Bombyx mori nucleopolyhedrovirus (BmNPV) is predicted to contain six RING finger proteins: IAP1, ORF35, IAP2, CG30, IE2, and PE38. Several other members of the RING finger family have recently been shown to have the ubiquitin-ligase (E3) activity. We thus examined whether BmNPV RING finger proteins have the E3 activity. In vitro ubiquitination assay with the rabbit reticulocyte lysates and BmNPV RING finger proteins fused with maltose-binding protein (MBP) showed that four of them (IAP2, IE2, PE38, and CG30) were polyubiquitinated in the presence of zinc ion. Furthermore, MBP-IAP2, MBP-IE2, and MBP-PE38 were able to reconstitute ubiquitination activity in cooperation with the Ubc4/5 subfamily of ubiquitin-conjugating enzymes. Mutational analysis also showed that ubiquitination activity of MBP-IAP2, MBP-IE2, and MBP-PE38 were dependent on their RING finger motif. Therefore, these results suggest that IAP2, IE2, and PE38 may function as E3 enzymes during BmNPV infection.

Download Full-text