Expression and functional properties of proteins encoded in the x-II ORF of HTLV-I

• Published in: Virus Research Vol. 78; no. 1; pp. 35 - 43
• Main Authors: D'Agostino, Donna M., Zotti, Lorenza, Ferro, Tiziana, Cavallori, Ilaria, Silic-Benussi, Micol, Chieco-Bianchi, Luigi, Ciminale, Vincenzo
• Format: Book Review Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 2001
• Subjects: Amino Acid Sequence; Gene Expression; Genes, pX - physiology; HTLV-I; Human T-lymphotropic virus 1; Human T-lymphotropic virus 1 - genetics; Human T-lymphotropic virus 1 - metabolism; Mitochondria; Mitochondria - metabolism; Molecular Sequence Data; Nucleolus; Nucleus; Open Reading Frames; Retroviridae Proteins - genetics; Retroviridae Proteins - metabolism; Rex protein; RNA Splicing; RNA, Messenger - metabolism; RNA-Binding Proteins - metabolism; Splicing; virulence factors; X region; Nucleus; HTLV-I; Mitochondria; X region; Nucleolus; Splicing
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/S0168-1702(01)00282-9

With the aim of identifying viral proteins that contribute to the distinctive properties of HTLV-I biology and pathogenicity, several laboratories have investigated the coding potential of the X region of the genome, which includes five partially overlapping open reading frames (ORFs). We and others have shown that, in addition to the essential regulatory proteins Rex and Tax, a number of accessory proteins encoded in the X region can be produced by alternative splicing and multicistronic translation. One X region ORF, termed X-II, produces two protein isoforms named Tof/p30 II and p13 II, which are expressed from a doubly- and singly-spliced mRNA, respectively. Initial functional analyses demonstrated that Tof/p30 II is a nucleolar/nuclear protein that possesses a region capable of binding to RNA, and p13 II is a mitochondrial protein that alters the morphology and function of this organelle. Together with data from other laboratories demonstrating the production of antibodies and CTL against x-II ORF products in HTLV-I infected subjects and the requirement of this ORF for efficient viral replication in vivo, these findings suggest that further characterization of Tof/p30 II and p13 II will yield insight into remaining undefined aspects of HTLV-I pathogenicity and replication.