In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

Input: Consider Input: Npl4 is likely to be the most upstream factor recognizing Lys48-linked polyubiquitylated substrates in the proteasomal degradation pathway in yeast. Along with Ufd1, Npl4 forms a heterodimer (UN), and functions as a cofactor for the Cdc48 ATPase. Here, we report the crystal structures of yeast Npl4 in complex with Lys48-linked diubiquitin and with the Npl4binding motif of Ufd1. The distal and proximal ubiquitin moieties of Lys48-linked diubiquitin primarily interact with the C-terminal helix and N-terminal loop of the Npl4 C-terminal domain (CTD), respectively. Mutational analysis suggests that the CTD contributes to linkage selectivity and initial binding of ubiquitin chains. Ufd1 occupies a hydrophobic groove of the Mpr1/Pad1 N-terminal (MPN) domain of Npl4, which corresponds to the catalytic groove of the MPN domain of JAB1/MPN/Mov34 metalloenzyme (JAMM)-family deubiquitylating enzyme. This study provides important structural insights into the polyubiquitin chain recognition by the Cdc48-UN complex and its assembly.

Output: Structural insights into ubiquitin recognition and Ufd1 interaction of Npl4

Input: Consider Input: Porcine blood mononuclear cells (PBMC) were shown to produce interferon-a (IFNa) following incubation with cells infected by a coronavirus, transmissible gastroenteritis virus. Monoclonal antibodies (mAb) with specificities for leukocyte subsets and major histocompatibility complex (MHC) antigens were used to characterize IFNa producer cells. The production of IFNa was found to be a function of non-phagocytic, non-adherent, non-T, non-B, CD4 + (and to a lesser extent CD8 +) MHC-class-II-positive ceils. Furthermore, addition of anti-MHC (class II) mAb during PBMC incubation with virus-infected cells reduced IFN yields, suggesting that masking of these surface antigens alters PBMC responsiveness to IFN induction.

Output: CHARACTERIZATION OF BLOOD MONONUCLEAR CELLS PRODUC- ING IFNa FOLLOWING INDUCTION BY CORONAVIRUS-INFECTED CELLS (PORCINE TRANSMISSIBLE GASTROENTERITIS VIRUS)

Input: Consider Input: Potent effective antiviral drugs recently have been licensed for several viral diseases, ushering in a new era in the treatment of viral diseases. At the same time, we have seen widespread adoption of rapid diagnostic tests to identify specific viral etiologies. These developments bring us to a point where the diagnosis and effective treatment of many viral diseases are commonplace. Several antiviral agents and their targets will be examined in this review. Acyclovir is effective against herpes simplex virus and varicella zoster virus; ribavirin, recently introduced, is effective against respiratory syncytial virus; amantadine is effective against the influenza type A viruses. Anticytomegalovirus agents, antihuman immunodeficiency virus agents, and immunomodulators such as the interferons are under investigation. Older agents such as adenosine arabinoside and idoxuridine are being replaced by newer, more effective agents. It has taken us a long time to reach this point because rendering a virus inactive is a more formidable feat than killing a bacteria. Bacteria reproduce outside of human cells and have several unique features that distinguish them from human cells. Viruses, in contrast, reproduce within human cells and have fewer unique features that selectively can be inhibited. 36 In recent years, several unique features in the process of a viral infection have been identified as target points for interference or inhibition. These unique steps in the process and the interfering compounds are the subject of this review. Acyclovir (Zovirax) currently is the most effective agent against several herpesviruses. It is a synthetic acyclic purine (guanosine) nucleoside ana-
Output: Antiviral Agents