The carboxy-terminal fragment of nucleolin interacts with the nucleocapsid domain of retroviral gag proteins and inhibits virion assembly.

A yeast two-hybrid screen for cellular proteins that interact with the murine leukemia virus (MuLV) Gag protein resulted in the identification of nucleolin, a host protein known to function in ribosome assembly. The interacting fusions contained the carboxy-terminal 212 amino acids of nucleolin [Nuc(212)]. The nucleocapsid (NC) portion of Gag was necessary and sufficient to mediate the binding to Nuc(212).

Amino acid substitutions in the CA protein of Moloney murine leukemia virus that block early events in infection.

The capsid domain (CA) of the retroviral Gag protein is a major constituent of the virion core. To examine the role of this protein in M-MuLV morphogenesis and replication, a series of substitution mutations affecting the central region of CA were introduced into an infectious proviral DNA. The altered DNAs were introduced into cells, and the resulting lines were analyzed for production of infectious virions.

Mutational analysis of interactions between the Gag precursor proteins of murine leukemia viruses.

The yeast two-hybrid system was used to test for interactions among the Gag precursor proteins of three members of the murine leukemia virus family. These Gag proteins all interact with each other in all combinations, but do not interact with the distantly related HIV-1 Gag. A series of deletion mutants of Moloney MuLV were examined to determine the minimal interaction domain.

Abl-interactor-1, a novel SH3 protein binding to the carboxy-terminal portion of the Abl protein, suppresses v-abl transforming activity.

A novel cellular protein, Abl-interactor-1 (Abi-1), which specifically interacts with the carboxy-terminal region of Abl oncoproteins, has been identified in a mouse leukemia cell line. The protein exhibits sequence similarity to homeotic genes, contains several polyproline stretches, and includes a src homology 3 (SH3) domain at its very carboxyl terminus that is required for binding to Abl proteins. The abi-1 gene has been mapped to mouse chromosome 2 and is genetically closely linked to the c-abl locus.