Biology subjects

Kleaveland, B.

Publications and source records attributed to Kleaveland, B..

4 recordsLinked to original sources

bioRxiv2026

Argonaute-2 slicing of Rtl1 promotes skeletal muscle development and postnatal survival

Argonaute (AGO) proteins associate with small guide RNAs to bind and repress mRNA targets. AGO2 is the primary AGO slicer in mammals, cleaving RNAs that base-pair extensively to its guide RNA. Disrupting the slicing activity of AGO2 in mice causes neonatal lethality, however, the specific cell types and substrates that contribute to this lethality are not known. Through a combination of genetic, histologic, and molecular approaches, we identify retrotransposon-like-1 (Rtl1) as a key AGO2 slicing substrate in placental endothelium and skeletal muscle, and show that AGO2 slicing in skeletal muscle, but not endothelium, is required for postnatal viability. Loss of AGO2 slicing causes cell-autonomous, pathologic changes in skeletal muscle, characterized by larger fibers, increased central nuclei, prominent central clearings, and induction of transcripts associated with heat shock proteins. Induced expression of RTL1, a domesticated retrotransposon-derived protein that can self-assemble into viral-like capsids, activates a similar heat shock protein response in cultured myoblasts, underscoring the importance of limiting excess RTL1 during muscle development. Taken together, our findings demonstrate a critical role for AGO2 slicing in skeletal muscle development that is, at least in part, due to its repression of a domesticated retrotransposon.

molecular biology↗

bioRxiv2025

Derepression of a single microRNA target causes female infertility in mice

The miR-200a and miR-200b families control mouse ovulation and are essential for female fertility. The ZEB1 transcription factor is a conserved target of both families and has been implicated as a key player in female fertility at multiple levels. Using gene-edited mice that express a miR-200a/b-resistant form of Zeb1, we found that derepression of Zeb1 in the female pituitary caused decreased production of luteinizing hormone and anovulatory infertility. These phenotypes were accompanied by widespread changes in pituitary gene expression characterized by decreased levels of ZEB1 targets, which include the miR-200a/b miRNAs, as expected from the miR-200a/b-ZEB1 double-negative feedback loop. Also observed were increased levels of mesenchymal genes, neuronal genes, and miR-200a/b targets. These results show that a double-negative feedback loop centered on the miRNA regulation of a single transcription factor can significantly influence the expression of thousands of genes and have dramatic phenotypic consequences.

molecular biology↗

bioRxiv2023

The widespread influence of ZSWIM8 on microRNAs during mouse embryonic development

MicroRNAs (miRNAs) pair to sites in mRNAs to direct the degradation of these RNA transcripts. Conversely, certain RNA transcripts can direct the degradation of particular miRNAs. This target-directed miRNA degradation (TDMD) requires the ZSWIM8 E3 ubiquitin ligase. Here, we report the function of ZSWIM8 in the mouse embryo. Zswim8-/- embryos were smaller than their littermates and died near the time of birth. This highly penetrant perinatal lethality was apparently caused by a lung sacculation defect attributed to failed maturation of alveolar epithelial cells. Some mutant individuals also had heart ventricular septal defects. These developmental abnormalities were accompanied by aberrant accumulation of >50 miRNAs observed across 12 tissues, which often led to enhanced repression of their mRNA targets. These ZSWIM8-sensitive miRNAs were preferentially produced from genomic miRNA clusters, and in some cases, ZSWIM8 caused a switch in the dominant strand that accumulated from a miRNA hairpin--observations suggesting that TDMD provides a mechanism to uncouple co-produced miRNAs from each other. Overall, our findings indicate that the regulatory influence of TDMD in mammalian biology is widespread and posit the existence of many yet-unidentified transcripts that trigger miRNA degradation.

molecular biology↗

bioRxiv2018

A Network of Noncoding Regulatory RNAs Acts in the Mammalian Brain

Noncoding RNAs (ncRNAs) play increasingly appreciated gene-regulatory roles. Here, we describe a regulatory network centered on four ncRNAs--a long ncRNA, a circular RNA, and two microRNAs--using gene editing in mice to probe the molecular consequences of disrupting key components of this network. The long ncRNA Cyrano uses an extensively paired site to miR-7 to trigger destruction of this microRNA. Cyrano-directed miR-7 degradation is much more efficient than previously described examples of target-directed microRNA degradation, which come from studies of artificial and viral RNAs. By reducing miR-7 levels, Cyrano prevents repression of miR-7-targeted mRNAs and enables the accumulation of Cdr1as, a circular RNA known to regulate neuronal activity. Without Cyrano, excess miR-7 causes cytoplasmic destruction of Cdr1as, in part through enhanced slicing of Cdr1as by a second miRNA, miR-671. Thus, several types of ncRNAs can collaborate to establish a sophisticated regulatory network.\n\nHIGHLIGHTSA long noncoding RNA, a circular RNA, and two microRNAs form a regulatory network\n\nThe Cyrano long noncoding RNA directs potent, multiple-turnover destruction of miR-7\n\nUnchecked miR-7 prevents accumulation of Cdr1as circular RNA in cytoplasm of neurons miR-7 prevents this accumulation by enhancing the miR-671-directed slicing of Cdr1as

molecular biology↗