Project description:Transposable elements constitute nearly half of the mammalian genome and play important roles in genome evolution. While a multitude of both transcriptional and post-transcriptional mechanisms exist to silence transposable elements, control of transposition in vivo remains poorly understood. MOV10, an RNA helicase, is an inhibitor of mobilization of retrotransposons and retroviruses in cell culture assays. Here we report that MOV10 restricts LINE1 retrotransposition in mice. Although MOV10 is broadly expressed, its loss causes only incomplete penetrance of embryonic lethality, and the surviving MOV10-deficient mice are healthy and fertile. Biochemically, MOV10 forms a complex with UPF1, a key component of the nonsense-mediated mRNA decay pathway, and primarily binds to the 3' UTR of somatically expressed transcripts in testis. Consequently, loss of MOV10 results in an altered transcriptome in testis. Analyses using a LINE1 reporter transgene reveal that loss of MOV10 leads to increased LINE1 retrotransposition in somatic and reproductive tissues from both embryos and adult mice. Moreover, the degree of LINE1 retrotransposition inhibition is dependent on the Mov10 gene dosage. Furthermore, MOV10 deficiency reduces reproductive fitness over successive generations. Our findings demonstrate that MOV10 attenuates LINE1 retrotransposition in a dosage-dependent manner in mice.
Project description:The La-related protein LARP7 has been mainly described as a component of the 7SK small nuclear ribonucleoprotein (snRNP) complex, which negatively regulates RNA polymerase II by sequestering the positive transcription elongation factor b (P-TEFb). In our studies, we discovered a novel, 7SK snRNP-independent function of LARP7. We show that LARP7 interacts with the U6 spliceosomal RNA as well as with the small nucleolar RNAs (snoRNAs) directing the 2'-O-methylations of U6. To investigate the relevance of this interaction, U6 or U2 snRNAs were purified from total RNA by pulldown of biotinylated antisense oligonucleotides and the occurence of 2’-O-methylations was investigated by RiboMeth-seq analysis. A comparison between U6 and U2 snRNA isolated from HEK293 wildtype or LARP7 knockout cell lines revealed that 2’-O-methylations of the U6 snRNA are specifically lost in the absence of LARP7. Alazami syndrome is a form of primary dwarfism associated with mutations in the LARP7 gene. RiboMeth-seq analyses performed with RNA isolated from blood samples of two Alazami patients or healthy parents as well as from B-lymphoblastoid cell lines (B-LCLs) derived from an Alazami patient and from a healthy parent confirmed the impact of mutant LARP7 protein variants on the 2’-O-methylation profile of the U6 snRNA.
Project description:Anti-LARP7 RNA immunoprecipitation (RIP) coupled with RNA-seq assays showed significant enrichment of U6 snRNA, but not other 4 spliceosomal snRNAs, in LARP7 complexes in adult mouse testis.
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3M-bM-^@M-^Y end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1M-NM-^T fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN. the 3' termini of U6 or tagged-U6 species from the indicated mutant cells were compared to wt yeast strain
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3M-bM-^@M-^Y end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1M-NM-^T fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN. The 3' termini of total RNA containing 2'3' cyclic phosphate from Mpn1-proficient and deficient human and yeast cells was sequenced
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3M-bM-^@M-^Y end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1M-NM-^T fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN. the 3' termini of human U6, U6atac and vtRNA1-1 transcripts from PN patient derived cells and from PN patient cells, compensated with hMPN1 were sequenced.
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3’ end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1Δ fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN.
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3’ end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1Δ fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN.
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3’ end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1Δ fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN.