Biology subjects

Genova, R.

Publications and source records attributed to Genova, R..

2 recordsLinked to original sources

bioRxiv2024

Chemoreceptor family in plant-associated bacteria responds preferentially to the plant signal molecule glycerol 3-phosphate

Plant pathogens and plant-associated bacteria contain about twice as many chemoreceptors as the bacterial average, indicating that chemotaxis is particularly important for bacteria-plant interactions. However, information on the corresponding chemoreceptors is limited. In this study, we identified the chemoreceptor PacP from the phytopathogen Pectobacterium atrosepticum, which exclusively recognized C3 phosphorylated compounds at its sCache ligand binding domain, mediating chemoattraction. Using a motif of PacP amino acid residues involved in ligand binding, we identified a chemoreceptor family, termed sCache_PC3, that was specific for C3 phosphorylated compounds. Isothermal titration calorimetry studies revealed that family members preferentially bound glycerol 3-phosphate, a key plant signaling molecule. Additionally, family members recognized glycerol 2-phosphate and glycolysis intermediates glyceraldehyde 3-phosphate, dihydroxyacetone phosphate and 3-phosphoglycerate. This study presents the first evidence of chemoreceptors that bind phosphorylated compounds. We show that the sCache_PC3 family has evolved from an ancestral sCache domain that respond primarily to Krebs cycle intermediates. Members of the sCache_PC3 family were mainly found in bacteria that interact with plants, including many important plant pathogens such as Brenneria, Dickeya, Musicola, Pectobacterium, and Herbaspirillum. Glycerol 3-phosphate is a signal molecule that is excreted by plants in response to stress and infection. Chemotaxis towards this molecule may thus be a means for bacteria to localize stressed plants and move to infection sites. This study lays the groundwork for investigating the functional importance of chemotaxis to phosphorylated C3 compounds in plant-bacteria interactions and virulence. Significance statementThe bacterial lifestyle has shaped the evolution of signal transduction systems, and the number and type of chemoreceptors varies greatly between bacteria occupying various ecological niches. Our understanding of the relationship between lifestyle and chemoreceptor function is limited and the discovery of a chemoreceptor family in plant-associated bacteria that primarily responds to an important plant signal molecule is a significant advancement, allowing for further studies to determine its physiological relevance. The lack of knowledge about signals recognized by bacterial receptors is currently a major challenge in microbiology. This study illustrates the potential of combining experimental ligand screening with computational ligand prediction to identify signals recognized by uncharacterized receptors.

microbiology↗

bioRxiv2020

A mouse model of Bardet-Biedl Syndrome has impaired fear memory, which is rescued by lithium treatment

Primary cilia are microtubule-based organelles present on most cells that regulate many physiological processes, ranging from maintaining energy homeostasis to renal function. However, the role of these structures in the regulation of behavior remains unknown. To study the role of cilia in behavior, we employ mouse models of the human ciliopathy, Bardet-Biedl Syndrome (BBS). Here, we demonstrate that BBS mice have significant impairments in context fear conditioning, a form of associative learning. Moreover, we show that postnatal deletion of BBS gene function, as well as congenital deletion, specifically in the forebrain, impairs context fear conditioning. Analyses indicated that these behavioral impairments are not the result of impaired hippocampal long-term potentiation. However, our results indicate that these behavioral impairments are linked to impaired hippocampal neurogenesis. Two-week treatment with lithium chloride partially restores the proliferation of hippocampal neurons which leads to a rescue of context fear conditioning. Overall, our results identify a novel role of cilia genes in hippocampal neurogenesis and long-term context fear conditioning. Author summaryThe primary cilium is a microtubule-based membranous projection on the cell that is involved in multiple physiological functions. Patients who have cilia dysfunction commonly have intellectual disability. However, it is not known how cilia affect learning and memory. Studying mouse models of a cilia-based intellectual disability can provide insight into learning and memory. One such cilia-based intellectual disability is Bardet-Biedl Syndrome (BBS), which is caused by homozygous and compound heterozygous mutations of BBS genes. We found that a mouse model of BBS (Bbs1M390R/M390R mice) has learning and memory defects. In addition, we found that other mouse models of BBS have similar learning and memory defects. These BBS mouse models have difficulty associating an environment with an aversive stimulus, a task designed to test context fear memory. This type of memory involves the hippocampus. We found that Bbs1M390R/M390R mice have decreased cell production in the hippocampus. Treating Bbs1M390R/M390R mice with a compound (lithium) that increases cell production in the hippocampus improved the learning and memory deficits. Our results demonstrate a potential role for cilia in learning and memory, and indicate that lithium is a potential treatment, requiring further study, for the intellectual disability phenotype of BBS.

animal behavior and cognition↗