THE GLYCOPROTEINS OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS AND THEIR ROLE IN INFECTION AND IMMUNITY

The porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogen of swine and is known to cause abortion and infertility in pregnant sows and respiratory distress in piglets. PRRSV contains a major glycoprotein (GP5) and three minor glycoproteins (GP2a, GP3, and GP4) on the virion envelope, all of which are required for infectious virus production. To study their interactions amongst each other and with a cellular receptor for PRRSV, CD163, I cloned each of the viral glycoproteins and CD163 in various expression vectors. My studies have shown that while the GP2a, GP3, and GP4 are co-translationally glycosylated, the GP5 is post-translationally glycosylated. By using co-immunoprecipitation (co-IP) assays, strong interaction was demonstrated between GP4 and GP5 proteins, although weak interactions among the other envelope glycoproteins were also detected. Further, GP4 was found to mediate interactions leading to formation of multiprotein glycoprotein complex. My results also show that GP2a and GP4 proteins are the only two GPs that specifically interact with the CD163 molecule and that glycosylation of these GPs is required for efficient interaction. Based on these studies, I have developed an interactome map of the viral GPs and CD163 and have proposed a model of the viral glycoprotein complex and its interaction with CD163. Studies reported here also show that glycan addition at residue 184 (N184) of GP2a, and residues N42, N50, and N131 of GP3 is essential for recovery of infectious virus. Although single site glycosylation mutants of GP4 had no effect on infectious virus production, introduction of double mutations was lethal. The loss of glycan moieties of GP2a, GP3, and GP4 proteins had no effect on host neutralizing antibody production. Overall, I conclude that the PRRSV glycoproteins are co-translationally and post-translationally glycosylated, the GP4 protein is central to mediating interglycoprotein interactions, and along with GP2a, serves as the viral attachment protein that is responsible for interactions with the viral receptor, CD163. Further, glycosylation of GP2a, GP3, and GP4 proteins is required for infectious virus production, efficient interaction with CD163, but does not play any role in neutralizing antibody response in infected animals.

Using Nebraska's Beginning Farmer Tax Credit Program

Many farm or ranch families that are attempting to bring a son or daughter back into their business experience a strain on the cash flow. Recent changes to Nebraska's Beginning Farmer Tax Credit Program provide an attractive incentive that can be very beneficial to those families. Regulation changes made in 2008 now allow parents to rent agricultural assets to their own children.

Using Nebraska’s Beginning Farmer Tax Credit Program

Many farm or ranch families that are attempting to bring a son or daughter back into their business experience a strain on the cash flow. After all, a business that has been providing enough income for one family to live on, must now not only generate adequate income for the parents living expenses, but also attempt to provide enough income for a second family, the successor. Recent changes to Nebraska’s Beginning Farmer Tax Credit Program provide an attractive incentive that can be very beneficial for family farming/ranching operations that are trying to bring a family member back into their business. Regulation changes made in 2008 now allow parents to rent agricultural assets to their own children.

RP97-43 Tax Planning When Buying or Selling a Farm

If you're like most farmers, one of your key goals is to maximize after-tax earnings. The more money left over after you've paid your farm bills land your taxes, the more you and your family will have to spend. You can increase thos enet earnings in sveral ways: by increasing production, by decreasing cost of supplies oer by finding a way to get more for your produce. But there's another way to increase your after-tax earnings. One that many farmers oculd afford to spen dmore time on: decreasing taxes. The key to avoiding unnecessary taxes is tax planning. This publication will help you do just that: plan for the future.