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Biomedical subjects

G S Schneider

Publications and source records attributed to G S Schneider.

5 recordsLinked to original sources
PubMed1996

An essential domain in Saccharomyces cerevisiae U14 snoRNA is absent in vertebrates, but conserved in other yeasts.

U14 is a small nucleolar RNA (snoRNA) required for early cleavages of eukaryotic precursor rRNA. The U14 RNA from Saccharomyces cerevisiae is distinguished from its vertebrate homologues by the presence of a stem-loop domain that is essential for function. This element, known as the Y-domain, is located in the U14 sequence between two universal sequences that base pair with 18S rRNA. Sequence data obtained for the U14 homologues from four additional phylogenetically distinct yeasts showed the Y-domain is not unique to S.cerevisiae. Comparison of the five Y-domain sequences revealed a common stem-loop structure with a conserved loop sequence that includes eight invariant nucleotides. Conservation of these features suggests that the Y-domain is a recognition signal for an essential interaction. Several plant U14 RNAs were found to contain similar structures, though with an unrelated consensus sequence in the loop portion. The U14 gene from the most distantly related yeast, Schizosaccharomyces pombe, was found to be active in S.cerevisiae, showing that Y-domain function is conserved and that U14 function can be provided by variants in which the essential elements are embedded in dissimilar flanking sequences. This last result suggests that U14 function may be determined solely by the essential elements.

Base Composition↗
PubMed1993

SnR31, snR32, and snR33: three novel, non-essential snRNAs from Saccharomyces cerevisiae.

Genes for three novel yeast snRNAs have been identified and tested for essentiality. Partial sequence information was developed for RNA extracted from isolated nuclei and the respective gene sequences were discovered by screening a DNA sequence database. The three RNAs contain 222, 188 and 183 nucleotides and are designated snR31, snR32 and snR33, respectively. Each RNA is derived from a single copy gene. The SNR31 gene is adjacent to a gene for an unnamed protein associated with the cap-binding protein eIF-4E. The SNR32 gene is next to a gene for ribosomal protein L41 and the gene for SNR33 is on chromosome III, between two open reading frames with no known function. Genetic disruption analyses showed that none of the three snRNAs is required for growth. The new RNAs bring the number of non-spliceosomal snRNAs characterized thus far in S. cerevisiae to 14, of which only three are essential.

Base Sequence↗
PubMed1977

Surgical and nonsurgical management of facial paralysis following closed head injury.

The outcomes of facial nerve decompression, surgical exploration, and nonsurgical treatment for facial paralysis following closed head injury were analyzed in 30 patients with an intact facial nerve, and complete evaluation. Objective evaluation of outcome was achieved by calculation of a Facial Paralysis Recovery Profile and Recovery Index (Profile minus complications). Twelve of 15 patients with incomplete facial paralysis were treated medically. All followed patients with incomplete paralysis and bilaterally equal facial nerve excitability had a Recovery Index of + 10 (complete recovery of function, no complications). Three with partial denervation had a Recovery Profile of + 10 with mild contracture and synkinesis. The average Recovery Profiles for all patients treated by decompression, exploration, or nonsurgically were respectively 4.0, 5.7, and 5.7. The Recovery Indices were +1.8, +3, and +2.7, respectively. Where nerve excitability had become abnormal, facial nerve decompression was of no benefit in traumatic facial paralysis due to closed head injury. Nerve excitability tests of peripheral branches are of great value for prognosis and selection of patients who do not need surgical intervention. Substitution of facial nerve exploration for facial nerve decompression seems reasonable. Polytomography of the facial canal is invaluable in selection of patients for operation.

Adolescent↗