Sathaseevan, Anson et al. (2021) International Worm Meeting "Investigating the germline function of the RNA-binding protein cfim-1"

Sathaseevan, Anson, Subramanian, Aishwarya, Yu, Bin, Derry, William Brent, Eroglu, Matthew, Fluke, Stacey

[International Worm Meeting, 2021]

Post-transcriptional regulation is crucial to proper organismal and tissue-specific development. An abundance of work has uncovered the essentiality of the core repertoire of factors and complexes constituting the cleavage and polyadenylation (CPA) machinery in post-embryonic development. Despite these findings, there is a need to define the precise relationship between these factors and tissue-specific development. Here, we demonstrate a novel role for the RNA-binding protein cfim-1 in germline function. cfim-1 functions in the CFIm complex, which is associated with preferential utilization of distal cleavage sites of pre-mRNAs bound for maturation by the core CPA machinery. Ablation of cfim-1 function results in reduced brood sizes. This effect is exacerbated at higher temperatures where a completely penetrant sterility phenotype is observed. We employ a combination of genetic and imaging analysis tools to characterize the organization and morphology of cfim-1 ablated germlines, demonstrating a precocious organization of meiotic-proliferating cells along the distal-proximal axis of the germline at the sterility-inducing temperature. We further provide genetic evidence to suggest that these effects are specific to the CFIm complex and not a general effect of antagonizing the function of the core CPA machinery. Data mining of worm 3'-sequencing data reveals an enrichment of the UGUA motif that is canonically bound by the CFIm complex upstream of the proximal cleavage sites of genes undergoing preferential transcript isoform utilization in response to ablation of cfim-1. These data, in conjunction with our previous findings, may suggest a novel model of regulation in the worm whereby recruitment of the CFIm complex to proximal cleavage sites in cfim-1 regulated genes antagonizes usage of those sites by the core CPA machinery.

Natesan, Balasubramanian (2010) C. elegans: Development and Gene Expression, EMBL, Heidelberg, Germany "Entomopathogenic nematode Steinernema carpocapsae secreted protease role on host immune suppression"

Natesan, Balasubramanian

[C. elegans: Development and Gene Expression, EMBL, Heidelberg, Germany, 2010]

Entomopathogenic nematode Steinernema carpocapsae secreted protease role on host immune suppression Natesan Bala subramanian, Duarte Toubarro and Nelson Simes CIRN and Department of Biology, University of Azores , 9500-801 Ponta Delgada , Portugal . Steinernema carpocapsae is an entomopathogenic nematode symbiotically associated with the bacterium Xenorhabdus nematophila . This nematode secrete proteases on there secrete products. Proteases are well known catabolic functions and many tasks imposed by a parasitic life cycle. Serine proteases are the most extensively studied enzymes on host parasite interaction. Host defence mechanism including cellular and humoral reactions against invading organisms. In humoral system phenoloxidase is a key enzyme and c onsidering the parasite survival it may inhibit prophenoloxidase system, could be a key to successful parasitism. In order to study host immune suppression, the in fective third-stage (L3) S. carpocapsae nematodes were grown on 1% Galleria mellonella insect homogenate and then collect secretory products (SP). From the SP trypsin (Sc-TRYP) and chymo trypsin (Sc-CHYM) -like serine protease were identified, purified and characterized. I n vitro, 52.6 % and 63.7% prophenoloxidase suppression was observed for Sc-TRYP and Sc-CHYM respectively. Sc-TRYP could affect G. mellonella insect haemocyte causing cells to become spherical or round shape and actin filaments were detected with Phalloidintetramethylrhodamine showed some of them were disorganised in haemocytes. Sc-chym gene expression was analysed with induced and non induced insect homogenate for 6 to72 h. In vivo , purified Sc-CHYM imbibed beads showed, it could prevent haemocytes encapsulation and melanization by 12 and 24 h, respectively. The role of these proteases in host immune suppression will be discussed.