Maher, Shayda, Oh, Jun Young, Sternberg, Paul W, Gharib, Shahla, Wong, Wan-Rong, Brugman, Katherine I
[
MicroPubl Biol,
2021]
Retinoic acid (RA), the active metabolite of vitamin A, broadly regulates gene expression. The RA signaling pathway plays an essential role in embryonic development, including the development of the body axis, eye, brain, and heart (Ghyselinck & Duester, 2019). One of the key enzymes in the biosynthesis of RA is aldehyde dehydrogenase 1 family member A3 (ALDH1A3). ALDH1A3 converts retinaldehyde to retinoic acid and it is expressed early in forebrain development (McCaffery & Drager, 1994). Several mutations in ALDH1A3 have been implicated in patients with autosomal recessive microphthalmia and other neurological disorders (Fares-Taie et al., 2013; Roos et al., 2014). However, current animal models of ALDH1A3 have large truncations of the protein. Direct evidence of the effects of missense variants on ALDH1A3 protein activity has not yet been obtained.
[
Exp Cell Res,
2013]
Mammals have 10 RASSF proteins, which are characterized by the Ras-association (RA) domain. Among them, RASSF1 to RASSF6 have the Salvador/RASSF/Hippo (SARAH) domain and form the subclass C-terminal RASSF proteins. Drosophila genome has a single C-terminal RASSF, dRASSF. All these RASSF proteins are related to the tumor suppressive Hippo pathway, and are considered to function as tumor suppressors. Caenorhabditis elegans T24F1.3 encodes a protein with the RA and the SARAH domains. The amino acid sequences are 40% and 55% similar to those of RASSF1 in the RA and the SARAH domains, respectively. We have characterized T24F1.3 gene product and named it RSF-1 as RASSF1 homolog. RSF-1 is widely expressed in epithelial cells. About 14%
rsf-1 mutants exhibit defects in embryonal morphogenesis and the actin disorganization. The combinatorial synthetic lethal analysis demonstrates that the lethality is enhanced to more than 80% in
rsf-1 mutants with the WASP-family verprolin homologous protein complex-related gene depletions and corroborates the implication of RSF-1 in the regulation of actin cytoskeleton. In
rsf-1 mutants, the structures of muscle actin are preserved, but the swimming ability is impaired. Although we could not detect the direct physical interaction of LET-60 with RSF-1,
rsf-1 mutants suppress the multivulva phenotype of the active
let-60 mutants, suggesting that
rsf-1 genetically interacts with the Ras signaling.
[
International Worm Meeting,
2017]
Extracellular vesicles are emerging as an important aspect of intercellular communication by delivering a parcel of proteins, lipids even nucleic acids to specific target cells over short or long distances (Maas 2017). A subset of C. elegans ciliated neurons release EVs to the environment and elicit changes in male behaviors in a cargo-dependent manner (Wang 2014, Silva 2017). Our studies raise many questions regarding these social communicating EV devices. Why is the cilium the donor site? What mechanisms control ciliary EV biogenesis? How are bioactive functions encoded within EVs? EV detection is a challenge and obstacle because of their small size (100nm). However, we possess the first and only system to visualize and monitor GFP-tagged EVs in living animals in real time. We are using several approaches to define the properties of an EV-releasing neuron (EVN) and to decipher the biology of ciliary-released EVs. To identify mechanisms regulating biogenesis, release, and function of ciliary EVs we took an unbiased transcriptome approach by isolating EVNs from adult worms and performing RNA-seq. We identified 335 significantly upregulated genes, of which 61 were validated by GFP reporters as expressed in EVNs (Wang 2015). By characterizing components of this EVN parts list, we discovered new components and pathways controlling EV biogenesis, EV shedding and retention in the cephalic lumen, and EV environmental release. We also identified cell-specific regulators of EVN ciliogenesis and are currently exploring mechanisms regulating EV cargo sorting. Our genetically tractable model can make inroads where other systems have not, and advance frontiers of EV knowledge where little is known. Maas, S. L. N., Breakefield, X. O., & Weaver, A. M. (2017). Trends in Cell Biology. Silva, M., Morsci, N., Nguyen, K. C. Q., Rizvi, A., Rongo, C., Hall, D. H., & Barr, M. M. (2017). Current Biology. Wang, J., Kaletsky, R., Silva, M., Williams, A., Haas, L. A., Androwski, R. J., Landis JN, Patrick C, Rashid A, Santiago-Martinez D, Gravato-Nobre M, Hodgkin J, Hall DH, Murphy CT, Barr, M. M. (2015).Current Biology. Wang, J., Silva, M., Haas, L. A., Morsci, N. S., Nguyen, K. C. Q., Hall, D. H., & Barr, M. M. (2014). Current Biology.
[
Dev Dyn,
1998]
In a retinoic acid (RA) gene trap screen of mouse embryonic stem (ES) cells, a novel gene, named Aquarius (Aqr), was identified and characterized. The promoterless lacZ marker was used to trap the genomic locus and to determine the expression pattern of the gene. Aqr transcripts are strongly induced in response to RA in vitro. During embryogenesis, Aqr is expressed in mesoderm, in the neural crest and its target tissues, and in neuroepithelium. Expression was first detected at 8.5 days postcoitum, when neural crest cells are visible at the lateral ridges of the neural plate. The gene-trapped Aqr locus was transmitted through the mouse germ line in three genetic backgrounds. In the F2 generation, the expected mendelian ratio of 1:2:1 was observed in all backgrounds, indicating that homozygous mice are viable. Homozygotes are normal in size and weight and breed normally. The gene trap insertion, however, does not seem to generate a null mutation, because Aqr transcripts are still present in the homozygous mutant animals. The Aqr open reading frame has weak homology to RNA-dependent RNA polymerases (RRPs) of the murine hepatitis viruses and contains an RRP motif. Aqr was mapped to mouse chromosome 2 between regions E5 through F2 by using fluorescence in situ hybridization analysis.