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. Importantly, in the absence of LARP7, significantly less 2'-O-methylations are deposited on U6 affecting splicing fidelity. Mutations in the LARP7 gene have been associated with the Alazami syndrome, a form of primordial dwarfism characterized by intellectual disability. We describe a novel loss-of-function mutation of LARP7 occurring in Alazami patients and detect reduced 2'-O-methylations of U6 in patient-derived samples. Thus, aberrant posttranscriptional RNA modifications of the spliceosomal U6 snRNA may contribute to the development of this severe disease.
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. Importantly, in the absence of LARP7, significantly less 2'-O-methylations are deposited on U6 affecting splicing fidelity. Mutations in the LARP7 gene have been associated with the Alazami syndrome, a form of primordial dwarfism characterized by intellectual disability. We describe a novel loss-of-function mutation of LARP7 occurring in Alazami patients and detect reduced 2'-O-methylations of U6 in patient-derived samples. Thus, aberrant posttranscriptional RNA modifications of the spliceosomal U6 snRNA may contribute to the development of this severe disease.
Project description:Small RNAs exert an effect through diverse RNA interference pathways to transcriptionally or post-transcriptionally silence their targets. The Piwi-interacting RNAs (piRNAs) represent a germline-specific small RNA pathway where Piwi proteins themselves are thought to mediate piRNA biosynthesis. Here, we provide strong evidence for a piRNA amplification loop in zebrafish, in which Ziwi and Zili bind piRNAs of opposite polarity. Furthermore, we describe a function for Zili in transposon defense and germ cell differentiation, as well as a crucial function in meiosis, significantly extending the function of Piwi proteins beyond the control of transposable elements in vertebrates. small RNA from total gonads or Argonaute IPs were cloned and sequenced using 454 GS FLX system.
Project description:Small RNAs exert an effect through diverse RNA interference pathways to transcriptionally or post-transcriptionally silence their targets. The Piwi-interacting RNAs (piRNAs) represent a germline-specific small RNA pathway where Piwi proteins themselves are thought to mediate piRNA biosynthesis. Here, we provide strong evidence for a piRNA amplification loop in zebrafish, in which Ziwi and Zili bind piRNAs of opposite polarity. Furthermore, we describe a function for Zili in transposon defense and germ cell differentiation, as well as a crucial function in meiosis, significantly extending the function of Piwi proteins beyond the control of transposable elements in vertebrates.
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: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. Importantly, in the absence of LARP7, significantly less 2'-O-methylations are deposited on U6 affecting splicing fidelity. Mutations in the LARP7 gene have been associated with the Alazami syndrome, a form of primordial dwarfism characterized by intellectual disability. We describe a novel loss-of-function mutation of LARP7 occurring in Alazami patients and detect reduced 2'-O-methylations of U6 in patient-derived samples. Thus, aberrant posttranscriptional RNA modifications of the spliceosomal U6 snRNA may contribute to the development of this severe disease.
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. Importantly, in the absence of LARP7, significantly less 2'-O-methylations are deposited on U6 affecting splicing fidelity. Mutations in the LARP7 gene have been associated with the Alazami syndrome, a form of primary dwarfism characterized by intellectual disability. We describe a novel loss-of-function mutation of LARP7 occurring in Alazami patients and detect reduced 2'-O-methylations of U6 in patient-derived samples. Thus, aberrant posttranscriptional RNA modifications of the spliceosomal U6 snRNA may contribute to the development of this severe disease.