Transcription-dependent nucleolar cap localization and possible nuclear function of DExH RNA helicase RHAU

Multisubunit cullin-RING ubiquitin ligase 4 (CRL4)-DCAF12 recognizes the C-terminal degron containing acidic amino acid residues. However, its physiological roles and substrates are largely unknown. Purification of CRL4-DCAF12 complexes revealed a wide range of potential substrates, including MOV10, an “ancient” RNA-induced silencing complex (RISC) complex RNA helicase. We show that DCAF12 controls the MOV10 protein level via its C-terminal motif in a proteasome- and CRL-dependent manner. Next, we generated Dcaf12 knockout mice and demonstrated that the DCAF12-mediated degradation of MOV10 is conserved in mice and humans. Detailed analysis of Dcaf12-deficient mice revealed that their testes produce fewer mature sperms, phenotype accompanied by elevated MOV10 and imbalance in meiotic markers SCP3 and γ-H2AX. Additionally, the percentages of splenic CD4+ T and natural killer T (NKT) cell populations were significantly altered. In vitro, activated Dcaf12-deficient T cells displayed inappropriately stabilized MOV10 and increased levels of activated caspases. In summary, we identified MOV10 as a novel substrate of CRL4-DCAF12 and demonstrated the biological relevance of the DCAF12-MOV10 pathway in spermatogenesis and T cell activation.

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RNA Helicase A Regulates the Replication of RNA Viruses

Viruses ◽

10.3390/v13030361 ◽

2021 ◽

Vol 13 (3) ◽

pp. 361

Author(s):

Rui-Zhu Shi ◽

Yuan-Qing Pan ◽

Li Xing

Keyword(s):

Virus Replication ◽

Rna Binding ◽

Rna Viruses ◽

Rna Helicase ◽

Rna Helicase A ◽

Double Stranded Rna ◽

Binding Domains ◽

N Terminus

The RNA helicase A (RHA) is a member of DExH-box helicases and characterized by two double-stranded RNA binding domains at the N-terminus. RHA unwinds double-stranded RNA in vitro and is involved in RNA metabolisms in the cell. RHA is also hijacked by a variety of RNA viruses to facilitate virus replication. Herein, this review will provide an overview of the role of RHA in the replication of RNA viruses.

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Nuclear cGAS: sequestration and beyond

Protein & Cell ◽

10.1007/s13238-021-00869-0 ◽

2021 ◽

Author(s):

Juli Bai ◽

Feng Liu

Keyword(s):

Innate Immune ◽

Complex Nature ◽

Type I ◽

Replication Forks ◽

The Novel ◽

Nuclear Function ◽

Double Stranded Dna ◽

Open Questions ◽

Established Role ◽

Dependent Signaling Pathway

AbstractThe cyclic GMP-AMP (cGAMP) synthase (cGAS) has been identified as a cytosolic double stranded DNA sensor that plays a pivotal role in the type I interferon and inflammation responses via the STING-dependent signaling pathway. In the past several years, a growing body of evidence has revealed that cGAS is also localized in the nucleus where it is associated with distinct nuclear substructures such as nucleosomes, DNA replication forks, the double-stranded breaks, and centromeres, suggesting that cGAS may have other functions in addition to its role in DNA sensing. However, while the innate immune function of cGAS is well established, the non-canonical nuclear function of cGAS remains poorly understood. Here, we review our current understanding of the complex nature of nuclear cGAS and point to open questions on the novel roles and the mechanisms of action of this protein as a key regulator of cell nuclear function, beyond its well-established role in dsDNA sensing and innate immune response.

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