Nucleotide sequence of the human tRNA(UUGGln) gene

Genome-wide genetic associations with IFNγ response to smallpox vaccine

Smallpox is a deadly and debilitating disease that killed hundreds of millions of people in the past century alone. The use of Vaccinia virus-based smallpox vaccines led to the eradication of smallpox. These vaccines are remarkably effective, inducing the characteristic pustule or "take" at the vaccine site in >97 % of recipients, and inducing a wide spectrum of long-lasting humoral and cellular immune responses. The mechanisms behind inter-individual vaccine-response variability are likely to involve host genetic variation, but have not been fully characterized. We report here the first smallpox vaccine response genome-wide association study of over 1,000 recent recipients of Dryvax(®). The data presented here focus on cellular immune responses as measured by both production of secreted IFNγ and quantitation of IFNγ secreting cells by ELISPOT assay. We identified multiple significant SNP associations in genes (RASA1, ADRA1D, TCF7L1, FAS) that are critical components of signaling pathways that directly control lymphocyte IFNγ production or cytotoxic T cell function. Similarly, we found many associations with SNPs located in genes integral to nerve cell function; findings that, given the complex interplay between the nervous and immune systems, deserve closer examination in follow-up studies.

Nonsense suppression in mammalian cells

Mammalian cells contain suppressor tRNAs that can translate nonsense codons such as UAG and UGA localized at a specific site of natural mRNAs. For translation of these nonsense codons, a specific secondary or tertiary structure of mRNAs located in the region surrounding the translatable nonsense codon is required. In mammalian cells, transcriptional expression of the tRNA gene encoding UAG suppressor glutamine tRNA is repressed by the binding of a nuclear protein to a specific site in the 5'-flanking region of the gene. Based on these findings, we discuss the translational regulation of nonsense codons in mammalian mRNAs.

The processing of wild type and mutant forms of rat nuclear pre-tRNA(Lys) by the homologous RNase P

The 5' processing of rat pre-tRNA(Lys) and a series of mutant derivatives by rat cytosolic RNase P was examined. In standard, non-kinetic assays, mutant precursors synthesized in vitro with 5' leader sequences of 10, 17, 24, 25, and 46 nucleotides were processed to approximately equal levels and yielded precisely cleaved 5' processed intermediates with the normal 7-base pair aminoacyl stems. The construct containing the tRNA(Lys) with the 46-nucleotide leader was modified by PCR to give a series of pre-tRNA(Lys) mutants designed to measure the effect on processing by (1) substituting the nucleotide at the +1 position, (2) pairing and unpairing the +1 and +72 bases, (3) elongating the aminoacyl stem, and (4) disrupting the helix of the aminoacyl stem. Comparative kinetic analyses revealed that changing the wild type +1G to A, C, or U was well tolerated by the RNase P provided that compensatory changes at +72 created a base pair or a G.U noncanonical pair. Mutants with elongated aminoacyl stems that were produced either by inserting an additional base pair at +3:a + 69:a or by pairing the -1A with a +73U, were processed to yield 7-base pair aminoacyl stems, but with different efficiencies. The efficiency seen with the double insertion mutant was higher than even the wild type precursor, but the -1A-U + 73 mutant was a relatively poor substrate. Disrupting the aminoacyl stem helix by introducing a +7G G + 66 mispairing or by inserting a single G at the +3:a position dramatically reduced the processing efficiency, although the position of cleavage occurred precisely at the wild type cleavage site. However, the single insertion of a C at the +69:a position resulted in an efficiently cleaved precursor, but permitted a minor, secondary cleavage within the leader between the -6 and -5 nucleotides in addition to the dominant wild type scission.