Anti-FLAG tag antibody

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf75 (ac75) is a highly conserved gene of unknown function. In this study, we constructed an ac75 knockout AcMNPV bacmid and investigated the role of ac75 in the baculovirus life cycle. The expression and distribution of the Ac75 protein were characterized, and its interaction with another viral protein was analyzed to further understand its function. Our data indicated that ac75 was required for the nuclear egress of nucleocapsids, intranuclear microvesicle formation, and subsequent budded virion (BV) formation, as well as occlusion-derived virion (ODV) envelopment and embedding of ODVs into polyhedra. Western blot analyses showed that two forms, of 18 and 15 kDa, of FLAG-tagged Ac75 protein were detected. Ac75 was associated with both nucleocapsid and envelope fractions of BVs but with only the nucleocapsid fraction of ODVs; the 18-kDa form was associated with only BVs, whereas the 15-kDa form was associated with both types of virion. Ac75 was localized predominantly in the intranuclear ring zone during infection and exhibited a nuclear rim distribution during the early phase of infection. A phase separation assay suggested that Ac75 was not an integral membrane protein. A coimmunoprecipitation assay revealed an interaction between Ac75 and the integral membrane protein Ac76, and bimolecular fluorescence complementation assays identified the sites of the interaction within the cytoplasm and at the nuclear membrane and ring zone in AcMNPV-infected cells. Our results have identified ac75 as a second gene that is required for both the nuclear egress of nucleocapsids and the formation of intranuclear microvesicles. IMPORTANCE During the baculovirus life cycle, the morphogenesis of both budded virions (BVs) and occlusion-derived virions (ODVs) is proposed to involve a budding process at the nuclear membrane, which occurs while nucleocapsids egress from the nucleus or when intranuclear microvesicles are produced. However, the exact mechanism of virion morphogenesis remains unknown. In this study, we identified ac75 as a second gene, in addition to ac93, that is essential for the nuclear egress of nucleocapsids, intranuclear microvesicle formation, and subsequent BV formation, as well as ODV envelopment and embedding of ODVs into polyhedra. Ac75 is not an integral membrane protein. However, it interacts with an integral membrane protein (Ac76) and is associated with the nuclear membrane. These data enhance our understanding of the commonalities between nuclear egress of nucleocapsids and intranuclear microvesicle formation and may help to reveal insights into the mechanism of baculovirus virion morphogenesis.

This paper deals with the method developed for rain flagging over oceans using radar backscatter and noise-equivalent brightness temperature (TB) measured by a Ku-band pencil-beam scatterometer launched onboard the Oceansat-2 (OS2) satellite. The OS2 scatterometer (OSCAT) measures radar backscatter and TB by its two pencil-beam antennas at local incidence angles of similar to 49 degrees (inner) and similar to 57. (outer) in horizontal and vertical polarizations, respectively. These measurements are affected by rain and heavy clouds, in addition to the ocean surface winds, thus affecting retrieval of wind vectors. The characteristics of TB at OSCAT specifications have been studied based on radiative transfer simulations. The horizontally polarized TB is observed to be sensitive to both wind speed and rain, whereas the vertically polarized TB (TBV), typically at 57., is found to be insensitive to ocean surface wind speed but is sensitive to rain, indicating its typical utility for rain flagging. As the retrievals of wind vectors are affected by rain, then so are the associated cost functions and their characteristics under rain-free and rainy situations. A combined use of TBV and retrieval cost functions has been made for rain flagging needed in wind directional-ambiguity removal, as well as tagging the retrieval quality. A data-driven dynamical method has been developed to specifically utilize TBV for supporting rain detection in view of the slow temporal drift found in the OSCAT TB data. Rain flags have been generated from OSCAT 25-km grid L2A (Version 1.4) data for the period from November 2009 to August 2010, and the results of comparison with Tropical Rainfall Measuring Mission Precipitation Radar 2A25 data are presented.