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Paramyxovirus matrix (M) proteins are key drivers of virus particle assembly and budding at the plasma membrane. To identify regions important for the M protein function, we generated a series of deletion mutants of the bovine parainfluenza virus type 3 (BPIV3) M protein. We found that M proteins lacking 10 amino acids in the amino-terminal end (ΔN10) or 4 amino acids in the carboxyl-terminal end (ΔC4) did not support M-deficient BPIV3 virion release and M protein-induced virus-like particle (VLP) release. Both ΔN10 and ΔC4 retained M protein-M protein and M protein-nucleocapsid (N) protein interactions. However, neither was transported to the plasma membrane. Our results indicate that both amino- and carboxyl-terminal ends of the BPIV3 M protein are essential for M protein transport to the plasma membrane, where it facilitates virion and VLP release. [Display omitted] • M protein terminal ends are important for virion and VLP release. • M proteins without terminal ends were not transported. • The M protein YLDV sequence is critical for virion and VLP release. [ABSTRACT FROM AUTHOR]

Wound healing after closed-head injury is a significant medical issue. However, conventional models of focal traumatic brain injury, such as fluid percussion injury and controlled cortical impact, employ mechanical impacts on the exposed cerebral cortex after craniotomy. These animal models are inappropriate for studying gliosis, as craniotomy itself induces gliosis. To address this, we developed a closed-head injury model and named "photo injury", which employs intense light illumination through a thinned-skull cranial window. Our prior work demonstrated that the gliosis of focal cerebral lesion after the photo injury does not encompass artificial gliosis and comprises two distinct reactive astrocyte subpopulations. The reactive astrocytes accumulated in the perilesional recovery area actively proliferate and express Nestin, a neural stem cell marker, while those in distal regions do not exhibit these traits. The present study investigated the role of perilesional reactive astrocytes (PRAs) in wound healing using the ablation of reactive astrocytes by the conditional knockout of Stat3. The extensive and non-selective ablation of reactive astrocytes in Nestin-Cre:Stat3 f/f mice resulted in an exacerbation of injury, marked by increased inflammation and BBB disruption. On the other hand, GFAP-CreER T2 :Stat3 f/f mice exhibited the partial and selective ablation of the PRAs, while their exacerbation of injury was at the same extent as in Nestin-Cre:Stat3 f/f mice. The comparison of these two mouse strains indicates that the PRAs are an essential astrocyte component for wound healing after closed-head injury, and their anti-inflammatory and regenerative functions are significantly affected even by incomplete accumulation. In addition, the reporter gene expression in the PRAs by GFAP-CreER T2 indicated a substantial elimination of these cells and an absence of differentiation into other cell types, despite Nestin expression, after wound healing. Thus, the accumulation and subsequent elimination of PRA are proposed as promising diagnostic and therapeutic avenues to bolster wound healing after closed-head injury. • Gliosis after TBI was investigated without artificial gliosis by craniotomy. • Perilesional reactive astrocytes (PRAs) were selectively ablated. • Partial PRA ablation exacerbated wound healing. • Partial PRA ablation increased inflammation and BBB disruption. • Partial PRA ablation similarly influenced as total reactive astrocyte ablation. [ABSTRACT FROM AUTHOR]