The CCAAT-box transcription factor, NF-Y complex, mediates the specification of the IL1 neurons in C. elegans

A FMRFamide-like neuropeptide FLP-12 signaling regulates head locomotive behaviors in Caenorhabditis elegans

Neuropeptides play a critical role in regulating behaviors across organisms, but the precise mechanisms by which neuropeptides orchestrate complex behavioral programs are not fully understood. Here, we show that the FMRFamide-like neuropeptide FLP-12 signaling from the SMB head motor neurons modulates head locomotive behaviors, including stomatal oscillation in Caenorhabditis elegans. lim-4 mutants, in which the SMB neurons are not properly specified, exhibited various head and body locomotive defects, including stomatal oscillation. Chronic activation or inhibition of neuropeptidergic signaling in the SMB motor neurons resulted in a decrease or increase in stomatal oscillation, respectively. The flp-12 neuropeptide gene is expressed and acts in the SMB neurons to regulate head and body locomotion, including stomatal oscillation. Moreover, the frpr-8 G protein-couple receptor (GPCR) and gpa-7 Gα genes are expressed in the AVD command interneurons to relay the FLP-12 signal to mediate stomatal oscillation. Finally, heterologous expression of FRPR-8 either Xenopus oocytes or HEK293T cells conferred FLP-12 induced responses. Taken together, these results indicate that the C. elegans FMRFamide neuropeptide FLP-12 acts as a modulator of stomatal oscillation via the FRPR-8 GPCR and the GPA-7 G-protein.

PIEZO acts in an intestinal valve to regulate swallowing in C. elegans

Sensations of the internal state of the body play crucial roles in regulating the physiological processes and maintaining homeostasis of an organism. However, our understanding of how internal signals are sensed, processed, and integrated to generate appropriate biological responses remains limited. Here, we show that the C. elegans PIEZO channel, encoded by pezo-1, regulates food movement in the intestine by detecting food accumulation in the anterior part of the intestinal lumen, thereby triggering rhythmical movement of the pharynx, referred to as the pharyngeal plunge. pezo-1 deletion mutants exhibit defects in the pharyngeal plunge, which is rescued by PEZO-1 or mouse PIEZO1 expression, but not by PIEZO2, in a single isolated non-neuronal tissue of the digestive tract, the pharyngeal-intestinal valve. Genetic ablation or optogenetic activation of this valve inhibits or induces the pharyngeal plunge, respectively. Moreover, pressure built in the anterior lumen of the intestine results in a pezo-1-dependent pharyngeal plunge, which is driven by head muscle contraction. These findings illustrate how interoceptive processes in a digestive organ regulate swallowing through the PIEZO channel, providing insights into how interoception coordinates ingestive processes in higher animals, including humans.

The role(s) of NF-Y in development and differentiation

NF-Y is a conserved sequence-specific trimeric Transcription Factor -TF- binding to the CCAAT element. We review here the role(s) in development, from pre-implantation embryo to terminally differentiated tissues, by rationalizing and commenting on genetic, genomic, epigenetic and biochemical studies. This effort brings to light the impact of NF-YA isoforms on stemness and differentiation, as well as binding to distal vs promoter proximal sites and connections with selected TFs.

Nuclear factor Y is a pervasive regulator of neuronal gene expression

Nervous system function relies on the establishment of complex gene expression programs that provide neuron-type-specific and core pan-neuronal features. These complementary regulatory paradigms are controlled by terminal selector and parallel-acting transcription factors (TFs), respectively. Here, we identify the nuclear factor Y (NF-Y) TF as a pervasive direct and indirect regulator of both neuron-type-specific and pan-neuronal gene expression. Mapping global NF-Y targets reveals direct binding to the cis-regulatory regions of pan-neuronal genes and terminal selector TFs. We show that NFYA-1 controls pan-neuronal gene expression directly through binding to CCAAT boxes in target gene promoters and indirectly by regulating the expression of terminal selector TFs. Further, we find that NFYA-1 regulation of neuronal gene expression is important for neuronal activity and motor function. Thus, our research sheds light on how global neuronal gene expression programs are buffered through direct and indirect regulatory mechanisms.

A sex-specific switch in a single glial cell patterns the apical extracellular matrix

Apical extracellular matrix (aECM) constitutes the interface between every tissue and the outside world. It is patterned into diverse tissue-specific structures through unknown mechanisms. Here, we show that a male-specific genetic switch in a single C. elegans glial cell patterns the overlying aECM from a solid sheet to an ∼200 nm pore, thus allowing a male sensory neuron to access the environment. Using cell-specific genetic sex reversal, we find that this switch reflects an inherent sex difference in the glial cell that is independent of the sex identity of the surrounding neurons. Through candidate and unbiased genetic screens, we find that this glial sex difference is controlled by factors shared with neurons (mab-3, lep-2, and lep-5) as well as previously unidentified regulators whose effects may be glia specific (nfya-1, bed-3, and jmjd-3.1). The switch results in male-specific glial expression of a secreted Hedgehog-related protein, GRL-18, that we discover localizes to transient nanoscale rings at sites where aECM pores will form. Using electron microscopy, we find that blocking male-specific gene expression in glia prevents pore formation, whereas forcing male-specific glial gene expression induces an ectopic pore. Thus, a switch in gene expression in a single cell is necessary and sufficient to pattern aECM into a specific structure. Our results highlight that aECM is not a simple homogeneous meshwork, but instead is composed of discrete local features that reflect the identity of the underlying cells.

A sex-specific switch in a single glial cell patterns the apical extracellular matrix

Apical extracellular matrix (aECM) constitutes the interface between every tissue and the outside world. It is patterned into diverse tissue-specific structures through unknown mechanisms. Here, we show that a male-specific genetic switch in a single C. elegans glial cell patterns the aECM into a ∼200 nm pore, allowing a male sensory neuron to access the environment. We find that this glial sex difference is controlled by factors shared with neurons ( mab-3, lep-2, lep-5 ) as well as previously unidentified regulators whose effects may be glia-specific ( nfya-1, bed-3, jmjd-3.1 ). The switch results in male-specific expression of a Hedgehog-related protein, GRL-18, that we discover localizes to transient nanoscale rings at sites of aECM pore formation. Blocking male-specific gene expression in glia prevents pore formation, whereas forcing male-specific expression induces an ectopic pore. Thus, a switch in gene expression in a single cell is necessary and sufficient to pattern aECM into a specific structure.