Nicholas J. Deacon

Identification of two novel human immunodeficiency virus type 1 splice acceptor sites in infected T cell lines

The regulatory and accessory proteins of human immunodeficiency virus type 1 (HIV-1) are produced from singly or multiply spliced mRNAs. We have used HIV-1-specific oligonucleotide primer pairs in a polymerase chain reaction procedure on RNA from lymphocyte cell lines infected with HIV-1(228,200). The amplified products were analysed by hybridization with splice junction-specific oligonucleotide probes to determine splice donor/splice acceptor combination utilization, subcloned into a plasmid vector and the nucleotide sequences were obtained. Two novel splice acceptor sites have been identified.

Further studies on similarity of terminal nucleotide sequences of eukaryote mRNA—A possible mechanism of RNA splicing

Abstract In the previous report (Naora, Deacon & Fry, 1979) it was pointed out that certain regions of the 5′- and 3′-terminal nucleotide sequences, which are similar to each other, of human and rabbit globin and chicken ovalbumin mRNA were present within possible double-stranded hairpin structures of a mRNA precursor. Using complete or partial nucleotide sequencing data of mouse βmaj globin, silk fibroin and chicken ovalbumin chromosomal genes, the possible occurrence of double-stranded hairpin structure in the presumptive mRNA precursor (“HnRNA”) molecule has been reexamined. Assuming that both the 5′- and 3′-terminal nucleotide sequences of “HnRNA” correspond to those of mature mRNA, nucleotide matching assessment shows that the 5′- and 3′-terminal nucleotide sequences, which are similar to each other, of mouse βmaj globin and chickin ovalbumin “HnRNA” can in fact be accommodated within intramolecular double-stranded structures, together with the first and last exon-intron joint sites as the complementary sequences, respectively. In particular, the 5′-terminal region of chicken ovalbumin “HnRNA” appears to be the basic element for forming a thermodynamically stable double-stranded structure with each of the 11 other exon-intron or intron-exon joint sites. It is suggested that both the 5′- and 3′-terminal specific regions of these “HnRNA” serve as the basic structural element to allow two splicing sites to stand close together and that splicing takes place at these specific regions of the HnRNA molecule. It is also proposed that a sequential splicing to form mRNA may take place at the 5′-terminal specific region of ovalbumin “HnRNA”.