Michael A Miller et al. (2003) International Worm Meeting "Evidence of selection for chromosome repatterning"

Michael A Miller, David Greenstein, Asher Cutter, Sam Ward, Valerie Reinke

[International Worm Meeting, 2003]

Eukaryotic genomes from diverse species contain distinct patterns of homologous genes ordered along their chromosomes. Chromosomal patterns change when rearrangements such as translocations, duplications, deletions, or inversions occur. These observations raise two important questions. Are genes randomly distributed in genomes? If not, do chromosomal rearrangements have adaptive value? We are beginning to address these questions through studies of a sperm-sensing mechanism that controls the rate and efficiency of reproduction in C. elegans. Sperm stimulate oocyte meiotic maturation, oocyte mitogen-activated protein kinase activation, somatic gonadal sheath contraction, and spermathecal dilation using the major sperm protein (MSP) as a signaling molecule. We show that genes in these signaling pathways are nonrandomly distributed in the genome and cluster with twenty-eight msp genes located at three loci on chromosomes II and IV. Other tightly linked genes have been implicated in regulating MSP transcription or trafficking during spermatogenesis. We also detected overlapping, nonrandom distributions of genes that control the onset of oogenesis (via the translational regulation of fem-3), but not of genes in other delineated pathways. Therefore, we have defined clusters of reproductive genes that function in common pathways. To evaluate the magnitude of these clusters, we used a global microarray-based strategy to determine the chromosomal distributions of genes with upregulated germline transcriptional profiles. Large nonrandom aggregations of sperm-enriched and germline-enriched genes colocalize with the chromosomal regions we defined by functional studies. By contrast, muscle-enriched or dauer-enriched genes are proportionately represented in these regions. Our results strongly support the hypothesis that reproductive genes are nonrandomly distributed in the C. elegans genome. To investigate the significance of these reproductive clusters, we examined chromosomal distributions of related genes in C. briggsae and other metazoan genomes. Comparative mapping and phylogenetic studies suggest that these clusters were built by large numbers of chromosomal rearrangements occurring in two temporal phases. Because rearrangements generated nonrandom patterns within the C. elegans genome, selection is predicted to drive this (re)distribution process. Therefore, chromosomal rearrangements may have adaptive value. We will discuss reasons why clustering may confer a selective advantage and implications for genome evolution.

Michael A Miller et al. (2001) International C. elegans Meeting "MSP Signalling: Beyond the Sperm Cytoskeleton."

David Greenstein, Michael A Miller

[International C. elegans Meeting, 2001]

Sophisticated regulatory systems have evolved to coordinate fertilization and oocyte meiotic cell cycle progression. However, the molecular interactions that govern critical oocyte cell cycle transitions and their conservation in the metazoa are not clear. C. elegans oocytes, like those of most animals, arrest during meiotic prophase. Sperm promote the resumption of meiosis (maturation) and contraction of the smooth muscle-like gonadal sheath cells, which are necessary for ovulation. Using an in vivo bioassay, we have shown that the major sperm cytoskeletal protein (MSP) acts as a bipartite signal for both oocyte maturation and sheath contraction. During nematode sperm locomotion, MSP plays a role analogous to actin indicating that this 14 kDa sperm-specific protein has acquired extracellular signaling and intracellular cytoskeletal functions during evolution. Proteins with MSP-like domains have been found in plants, fungi, and other animals raising the possibility that MSP signaling functions may exist in other phyla. We are particularly interested in understanding how MSP promotes the resumption of meiosis in oocytes. A receptor for a maturation-promoting factor has not been identified in any animal. Thus, identifying and characterizing the MSP receptor(s) is a major goal. We are taking a genomic approach to identify receptor candidates. Using an in situ MSP binding assay, candidates can be quickly screened for binding following RNAi. In this assay, MSP-flouroscein specifically binds oocytes and sheath cells of the proximal gonad arm. MSP-flouroscein is active in promoting both oocyte maturation and sheath contraction in vivo . Binding is not observed in distal female gonads, male gonads, or following incubation with BSA-flouroscein. Preincubation with a 20-fold excess of unlabeled MSP completely abrogates MSP-flouroscein binding. Further, binding is not observed in emo-1(oz1) oocytes, which lack a functional secretory system due to a mutation in a Sec61p g homologue (Iwasaki et al., 1996). Using data from DNA microarrays (Reinke et al., 2000), we have identified three conserved transmembrane proteins whose transcripts are highly enriched in oocytes. MSP binding to oocytes is dramatically reduced in two loss of function backgrounds and enhanced in the other. Each gene is tightly linked to one of the two large MSP clusters in the genome--a finding of unknown significance. We currently have mutations in two genes and are doing detailed phenotypic analyses. We are also interested in examining protein localization in situ and evaluating MSP binding in a heterologous system. Our results will be discussed in the context of a new model for oocyte meiotic maturation. Iwasaki et al. (1996). J Cell Biol 134:699-714 Reinke et al. (2000). Mol Cell 6:605-616

Michael A Miller et al. (2002) Mid-west Worm Meeting "An Eph Receptor Sperm-Sensing Control Mechanism for Oocyte Meiotic Maturation"

David Greenstein, Paul J Ruest, Steven K Hanks, Mary Kosinski, Michael A Miller

[Mid-west Worm Meeting, 2002]

During sexual reproduction in most animals, oocytes arrest in meiotic prophase and resume meiosis (meiotic maturation or M-phase entry) in response to sperm or somatic cell signals (1). Despite progress in delineating mitogen-activated protein kinase (MAPK) and CDK/cyclin activation pathways involved in meiotic maturation, it is less clear how these pathways are regulated at the cell surface. In Caenorhabditis elegans, oocytes and somatic gonadal sheath cells sense the presence of sperm in the reproductive tract and prepare for fertilization (2). When sperm are absent, oocytes arrest in meiotic prophase for days (2). Sperm promote oocyte M-phase entry and MAPK activation using the major sperm protein (MSP) as a signaling molecule (3). MSP also functions in sperm locomotion, playing a role analogous to actin (4). Thus during evolution, MSP has acquired extracellular signaling and intracellular functions for reproduction. We present multiple lines of evidence that the VAB-1 Eph receptor protein-tyrosine kinase and a somatic gonadal sheath cell-dependent pathway, defined by the POU-homeobox gene ceh-18, negatively regulate oocyte M-phase entry and MAPK activation. MSP antagonizes these inhibitory circuits, in part by binding VAB-1 on oocytes and sheath cells. Eliminating vab-1 and ceh-18 function removes the dependence of meiotic maturation and ovulation on the presence of sperm. Therefore, this meiotic control mechanism resembles a cell cycle checkpoint (5) and may confer a selective advantage to hermaphrodites and females by conserving metabolically costly oocytes when sperm are unavailable for fertilization. MSP-domain proteins are found throughout the metazoa, including six in the human genome, and may regulate contact-dependent ephrin/Eph receptor signaling pathways.

Michael A Miller et al. (2002) East Coast Worm Meeting "An Eph Receptor Sperm-Sensing Control Mechanism for Oocyte Meiotic Maturation"

Michael A Miller, David Greenstein, Paul J Ruest, Mary Kosinski, Steven K Hanks

[East Coast Worm Meeting, 2002]

During sexual reproduction in most animals, oocytes arrest in meiotic prophase and resume meiosis (meiotic maturation or M-phase entry) in response to sperm or somatic cell signals (1). Despite progress in delineating mitogen-activated protein kinase (MAPK) and CDK/cyclin activation pathways involved in meiotic maturation, it is less clear how these pathways are regulated at the cell surface. In Caenorhabditis elegans, oocytes and somatic gonadal sheath cells sense the presence of sperm in the reproductive tract and prepare for fertilization (2). When sperm are absent, oocytes arrest in meiotic prophase for days (2). Sperm promote oocyte M-phase entry and MAPK activation using the major sperm protein (MSP) as a signaling molecule (3). MSP also functions in sperm locomotion, playing a role analogous to actin (4). Thus during evolution, MSP has acquired extracellular signaling and intracellular functions for reproduction. We present multiple lines of evidence that the VAB-1 Eph receptor protein-tyrosine kinase and a somatic gonadal sheath cell-dependent pathway, defined by the POU-homeobox gene ceh-18, negatively regulate oocyte M-phase entry and MAPK activation. MSP antagonizes these inhibitory circuits, in part by binding VAB-1 on oocytes and sheath cells. Eliminating vab-1 and ceh-18 function removes the dependence of meiotic maturation and ovulation on the presence of sperm. Therefore, this meiotic control mechanism resembles a cell cycle checkpoint (5) and may confer a selective advantage to hermaphrodites and females by conserving metabolically costly oocytes when sperm are unavailable for fertilization. MSP-domain proteins are found throughout the metazoa, including six in the human genome, and may regulate contact-dependent ephrin/Eph receptor signaling pathways.

Colonnello A et al. (2020) Neurotox Res "Correction to: Comparing the Neuroprotective Effects of Caffeic Acid in Rat Cortical Slices and Caenorhabditis elegans: Involvement of Nrf2 and SKN-1 Signaling Pathways."

Tunez I, Rubio-Lopez LC, Aguilera-Portillo G, Silva-Palacios A, Evaristo-Priego Y, Santamaria A, Galvan-Arzate S, Cortez-Nunez S, Aschner M, Rangel-Lopez E, Chen P, Colonnello A, Robles-Banuelos B, Garcia-Contreras R

[Neurotox Res, 2020]

One of the authors has incorrect family name spelling in the original article_. Michael Ashner should read as Michael Aschner.

Miller DM et al. (1992) Worm Breeder's Gazette "unc-4 LacZ Expression in A-Type Motor Neurons"

Miller DM, Niemeyer CJ

[Worm Breeder's Gazette, 1992]

unc-4 LacZ expression in A-type motor neurons David M. Miller and Charles J. Niemeyer, Dept. of Cell Biology, Duke Univ. Medical Ctr, Durham, NC 27710

Johnson, Christina K. et al. (2021) MicroPubl Biol

Miller III, David M., Johnson, Christina K., Bianchi, Laura

[MicroPubl Biol, 2021]

For Johnson, CK; Miller, DD; Bianchi, L (2021). Effect of the protease plasmin on C. elegans hyperactive DEG/ENaC channels MEC-4(d) and UNC-8(d). microPublication Biology. 10.17912/micropub.biology.000412.

Schultz, Jessica L. et al. (2013) International Worm Meeting "A Complex Issue: Understanding vMSP Receptor Heteromeric Complexing Behavior."

Miller, Michael, Lee, Se-Jin, Schultz, Jessica L., Han, Sung Min

[International Worm Meeting, 2013]

Amyotrophic Lateral Sclerosis (ALS) is a lethal neurodegenerative disease with an unknown pathogenesis and limited therapeutic treatments. A major limitation hindering the development of therapeutic treatments is a lack of understanding of the disease's molecular pathways. In humans, a P56S point mutation in the VAPB/ALS8 MSP domain is associated with ALS and late-onset spinal muscular atrophy (SMA) (Funke et al., 2010; Millecamps et al., 2010; Nishimura et al., 2004). The N-terminal MSP domain is cleaved from the C-terminus of the VAPB protein, and is secreted in a cell-type specific manner (Tsuda et al., 2008). However, the P56S mutation inhibits secretion of the MSP domain. Genetic and biochemical evidence support the hypothesis that the MSP domain interacts with the VAB-1 Eph receptor, ROBO/SAX-3 receptor, and CLR-1 Lar-like protein tyrosine phosphatase receptor, which are collectively called growth cone guidance receptors (Miller et al, 2001; Miller et al., 2003; Tsuda et al., 2008; Han et al., 2012). In C. elegans, secreted vMSP acts on CLR-1 and ROBO/SAX-3 receptors expressed in striated muscle, promoting Arp2/3-dependent actin remodeling. This remodeling is critical for proper placement of mitochondria to actin-rich myofilament I-bands (Han et al., 2012). We hypothesize that the vMSP receptors form heteromeric complexes to promote signaling critical for actin remodeling and correct mitochondria placement. To begin testing this hypothesis, I am expressing combinations of VAB-1, SAX-3, and CLR-1 in cultured cells and investigating putative complex formation via co-immunoprecipitation. My preliminary data suggest that SAX-3 complexes with both VAB-1 and CLR-1. Data will also be presented on the role of C. elegans VAPB/VPR-1 in regulating mitochondria in motor neurons. The results could provide insight into growth cone guidance receptor interactions and pathways involved in ALS.

Hengartner MO et al. (1992) Worm Breeder's Gazette "unc-50, a Gene Required for Acetylcholine Receptor Function, Encodes an Unfamiliar Protein"

Horvitz HR, Tsung N, Hengartner MO, Lewis JA

[Worm Breeder's Gazette, 1992]

unc-50, a gene requiired for acetylcholine receptor function, encodes an unfamiliar protein Michael Hengartner, Nancy Tsung, Jim Lewist, and Bob Horvitz HHMI, Dept. Biology, MIT, Cambridge, MA 02139, USA. t Division of Life Sciences, U. of Texas at San Antonio, San Antonio, IX 78249

Winek, Jessica L et al. (2011) International Worm Meeting "Unraveling the VAP MSP secretion mechanism."

Winek, Jessica L, Miller, Michael

[International Worm Meeting, 2011]

VAPs are evolutionarily conserved proteins with an N-terminal MSP (major sperm protein) domain and C-terminal transmembrane domain. A P56S substitution in the VAPB/ALS8 MSP domain is associated with amyotrophic lateral sclerosis (ALS) and late-onset spinal muscular atrophy (Nishimura et al., 2004). We have shown that VAP MSP domains are cleaved from the transmembrane domain and secreted into the extracellular environment (Tsuda et al., 2008). The P56S mutation inhibits secretion. Therefore, MSP secretion may play a critical role in ALS pathogenesis and understanding this secretion mechanism could lead to novel therapeutic strategies. MSP domains do not contain a signal peptide and are secreted by an unconventional mechanism (Kosinski et al., 2005). The goal of this project is to elucidate the mechanism by which neurons secrete VAP MSP domains. Recent work in yeast has shown that the Acb1 protein is secreted by a novel mechanism that depends on autophagy genes (Duran et al., 2010; Manjithaya et al., 2010). We are testing the hypothesis that this mechanism is essential for VAP MSP secretion. Our initial data suggests that MSP domains may have a similar secretion mechanism to the Acb-1 protein in Saccharomyces cerevisiae.