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T J Quinlan

Publications and source records attributed to T J Quinlan.

12 recordsLinked to original sources
PubMed1982

Innervation of the equine intrinsic laryngeal muscles.

The nerve supply to the intrinsic laryngeal muscles of the horse was studied by gross dissection and by electromyography which was carried out before, during and after section of various intralaryngeal nerve branches. The anatomical relationships and passage of the laryngeal nerves throughout the larynx were defined. Unlike the dog and man there was no evidence of the passage of motor nerve fibres from one side of the larynx to the other.

Journal Article↗
PubMed1979

Frequency difference between nuclear and polysomal sequences of poly(A)-containing RNA from cultured AKR mouse embryo cells.

The involvement of post-transcriptional mechanisms in the determination of the frequency distribution of messenger RNA sequences has been studied in cloned mouse embryo cells in culture. Hybridization kinetic experiments between poly(A)-containing RNA and complementary DNA have been used to study the alterations in frequencies which occur in those nuclear poly(A)-containing RNA sequences which are conserved in cytoplasmic poly-ribosomes. Sequences adjacent to nuclear poly(A) tracts are present in a much narrower frequency distribution in the nucleus than in polysomes, with a large proportion of the nuclear sequences present in an average frequency of about one molecule per cell. Few nuclear sequences appear to be present in more than ten copies per cell. A minimum of 70% of these sequences are also found in poly-ribosomal RNA but in greatly altered frequencies. Abundant sequences which comprise a major fraction of the poly(A)-containing polyribosomal RNA are derived from a small fraction of the nuclear poly(A)-adjacent RNA sequences. Very few nuclear poly(A)-adjacent sequences are present in a frequency characteristic of high abundance polysomal sequences. Conversely, poly(A)-containing polyribosomal RNA appears to contain few sequences which are present in as low a frequency as the majority of nuclear poly(A)-adjacent sequences. These observations suggest that post-transcriptional mechanisms play a major role in determining the steady-state frequency of polyribosome-associated messenger RNAs.

Animals↗
PubMed1978

The concept of mRNA abundance classes: a critical reevaluation.

Derivative plots have been constructed for hybridization reactions between polysomal poly(A)-containing RNA and oligo(dT)-primed cDNA. In one method the derivative was calculated directly from the data, and in the other, from a non-linear least squares fit using 9-10 ideal components. In some cases these methods yield very similar results and strongly suggest that the hybridization data support discrete components. Reactions with two and four major components indicate that the often-reported three abundance class model is only one of several possibilities for eukaryotic cells. In other situations neither method strongly suggests the presence of discrete components (in one case even after enrichment of the cDNA population by kinetic fractionation), implying that the components are closely spaced or that the entire mRNA population of those cells may not exist as discrete abundance classes. The universal occurrence of discrete abundance classes should be critically reexamined.

Animals↗
PubMed1977

Properties of a nuclear polyadenylate-protein complex from mouse ascites cells.

Ribonucleoprotein (RNP) subcomplexes containing at least 60% of the total nuclear poly(A) were isolated from mouse ascites cells; these 15 S ribonucleoprotein particles were most probably derived from larger hnRNA containing complexes. The buoyant density of the 15 S ribonucleoprotein in formaldehyde-CsCl was significantly less than that of the hnRNA-containing 30 S ribonucleoprotein subcomplex, indicating a higher proportion of protein (approximately 80%) in the 15 S ribonucleoprotein. The proteins partially protected the poly(A) from the action of ribonuclease T2. RNA isolated from purified 15 S ribonucleoprotein was estimated to be 190 to 200 nucleotides in length by gel electrophoresis, whereas the RNA from crude preparations was slightly larger. Base composition analysis of 32P-labeled crude 15 S RNP-RNA showed it to be rich in adenylate (70%) but containing a substantial amount of uridylate (20%). The base composition of RNA from purified complexes was approximately 90% adenyalte. Our results suggested that oligo(U) sequences from hnRNA could artificially associated with the poly(A) during preparation of 15 S RNP-RNA.

Animals↗
PubMed1974

Nuclear ribonucleoprotein complexes containing polyadenylate from mouse ascites cells.

Nuclear poly(A)-containing RNA of mouse ascites cells can be extracted in the form of 15-17S ribonucleoprotein complexes under conditions in which the bulk of the heterogeneous nuclear RNA is released as 30S complexes. The poly(A)-containing fraction of nuclear extracts has been resolved into two distinct components, 15 and 17 S; neither contains the two polypeptides of 30S ribonucleoprotein. The 17S particle contains approximately six polypeptide species of molecular masses 17,000-30,000 daltons. The 15S complex has four distinct polypeptides of higher molecular mass, including a prominent 80,000-dalton species.

Adenine Nucleotides↗