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S R Haynes

Publications and source records attributed to S R Haynes.

At least 37 records · Page 2Linked to original sources
PubMed1992

Accuracy of coagulation studies performed on blood samples obtained from arterial cannulae.

We have assessed the accuracy of coagulation studies in blood obtained from intra-arterial cannulae. Paired samples were studied in blood from 39 patients receiving intensive care; one sample was obtained by venepuncture and the other from an intra-arterial cannula after the apparatus deadspace plus 5 ml of blood had been discarded. Activated partial thromboplastin time (APTT) (with thromboplastin routinely used in our laboratory), prothrombin time (PT), thrombin time (TT), fibrinogen and heparin assays were measured on each sample. In 37 sample pairs, APTT was measured also using a different thromboplastin. The median difference between the sample pairs was 5.5 s for APTT (P = 0.032) and 1.0 s (P = 0.048) for TT, the times for arterial cannula samples being longer. There was no significant difference between arterial cannula and venepuncture samples for PT or fibrinogen concentration. Heparin assays revealed heparin contamination in samples obtained from arterial cannulae in 15 of 30 patients not receiving heparin. It is concluded that, when coagulation studies are performed using the techniques used routinely in our laboratory, a blood sample from an arterial cannula may give clinically misleading information because of contamination with small amounts of heparin, and that separate venepuncture is recommended.

Blood Coagulation Tests↗
PubMed1992

Heterogeneous nuclear ribonucleoprotein complexes and proteins in Drosophila melanogaster.

Pre-mRNAs cotranscriptionally associate with a small group of proteins to form heterogeneous nuclear ribonucleoprotein (hnRNP) complexes. We have previously identified two genes in Drosophila melanogaster, Hrb98DE and Hrb87F (i.e., genes at 98DE and 87F encoding putative hnRNA binding proteins), which encode five protein species homologous to the mammalian A-B hnRNP proteins. The studies presented herein show that antibodies against the RNP domains of Hrb98DE reacted with 10 to 15 distinct spots of 38 to 40 kDa in the basic region of two-dimensional gels. These nuclear proteins bound single-stranded nucleic acids and were extracted from Drosophila tissue culture cells as 40 to 80S hnRNP complexes in association with 300 to 800 nucleotide fragments of RNA. The peak of poly(A)+ RNA sequences was coincident with the peak of HRB proteins in sucrose gradients, strongly suggesting that the HRB complexes identified are Drosophila hnRNP complexes. The repertoire of HRB proteins did not change significantly during embryogenesis and was similar to that observed in Drosophila tissue culture cells. Analyses with peptide-specific antisera demonstrated that the major proteins in the hnRNP complex were encoded by the two genes previously identified. Although the Drosophila HRB proteins are only approximately 60% identical throughout the RNP domains to the mammalian A-B hnRNP proteins, features of the basic pre-mRNA packaging mechanism appear to be highly conserved between D. melanogaster and mammals.

Amino Acid Sequence↗
PubMed1992

The RNP motif protein family.

RNA-protein interactions play critical roles in a variety of important processes in the cell, such as mRNA splicing and translation. Many RNA binding proteins contain an approximately 80-aminoacid conserved sequence, the RNP motif, that has been shown in several cases to constitute the binding domain. As a class, RNP motif proteins bind many different RNAs with varying degrees of sequence specificity. A major area of current interest is the elucidation of the structure-function relationships in these proteins: the structure of the motif and the residues that are important for sequence-specific binding, the roles of the individual motifs in proteins with multiple RNP motifs, and the functions of other domains found in RNP motif proteins. Recent experiments have provided some insight into these issues and have paved the way for a more detailed understanding of this protein family.

Amino Acid Sequence↗
PubMed1991

The Drosophila Hrb87F gene encodes a new member of the A and B hnRNP protein group.

Nascent premessenger RNA transcripts are packaged into heterogeneous nuclear ribonucleoprotein (hnRNP) complexes containing specific nuclear proteins, the hnRNP proteins. The A and B group proteins constitute a major class of small basic proteins found in mammalian hnRNP complexes. We have previously characterized the Drosophila melanogaster Hrb98DE gene, which is alternatively spliced to encode four protein isoforms closely related to the A and B proteins. We report here that the Drosophila genome contains a family of genes related to the Hrb98DE gene. One member of the family, Hrb87F, is very homologous to Hrb98DE in both sequence and structure. The Hrb87F transcripts (1.7 and 2.2 kb) utilize two alternative polyadenylation sites, are abundant in ovaries and early embryos, and are present in lesser amounts throughout development. In one wildtype strain of Drosophila there is a naturally-occurring polymorphism in this gene due to the insertion of a 412 transposable element in the 3' untranslated region. The larger transcript is not produced in these files and thus is not required for viability. Sequence identities among the Drosophila Hrb proteins and the vertebrate A and B hnRNP proteins suggest that these proteins may form a distinct subfamily within the larger family of related RNA binding proteins.

Amino Acid Sequence↗
PubMed1991

Glycine loops in proteins: their occurrence in certain intermediate filament chains, loricrins and single-stranded RNA binding proteins.

Quasi-repetitive, glycine-rich peptide sequences are widespread in at least three distinct families of proteins: the keratins and other intermediate filament proteins, including nuclear lamins; loricrins, which are major envelope components of terminally differentiated epithelial cells; and single-stranded RNA binding proteins. We propose that such sequences comprise a new structural motif termed the 'glycine loop'. The defining characteristics of glycine loop sequences are: (1) they have the form x(y)n, where x is usually an aromatic or occasionally a long-chain aliphatic residue; y is usually glycine but may include polar residues such as serine, asparagine, arginine, cysteine, and rarely other residues; and the value of n is highly variable, ranging from 1 to 35 in examples identified to date. (2) Glycine-loop-containing domains are thought to form when at least two and to date, as many as 18, such quasi-repeats are configured in tandem, so that the entire domain in a protein may be 50-150 residues long. (3) The average value of n, the pattern of residues found in the x position and the non-glycine substitutions in the y position appear to be characteristic of a given glycine loop containing domain, whereas the actual number of repeats is less constrained. (4) Glycine loop sequences display a high degree of evolutionary sequence variability and even allelic variations among different individuals of the same vertebrate species. (5) Glycine loop sequences are expected to be highly flexible, but possess little other regular secondary structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Prolonged neuromuscular blockade with vecuronium in a neonate with renal failure.

An 11-day-old neonate with renal failure caused by dysplastic kidneys was anaesthetised with thiopentone, vecuronium, nitrous oxide and oxygen, for insertion of a long-term peritoneal dialysis catheter. Complete neuromuscular block of 210 minutes' duration ensued after the initial dose of vecuronium (97 micrograms/kg). Partial block persisted for a further 30 minutes. The prolonged neuromuscular block in this case may have been because of proportionately greater dependence on renal clearance of vecuronium in neonates.

Anesthesia, General↗
PubMed1990

The Drosophila Hrb98DE locus encodes four protein isoforms homologous to the A1 protein of mammalian heterogeneous nuclear ribonucleoprotein complexes.

The Drosophila Hrb98DE locus encodes proteins that are highly homologous to the mammalian A1 protein, a major component of heterogeneous nuclear ribonucleoprotein (RNP) particles. The Hrb98DE locus is transcribed throughout development, with the highest transcript levels found in ovaries, early embryos, and pupae. Eight different transcripts are produced by the use of combinations of alternative promoters, exons, and splice acceptor sites; the various species are not all equally abundant. The 3'-most exon is unusual in that it is completely noncoding. These transcripts can potentially generate four protein isoforms that differ in their N-terminal 16 to 21 amino acids but are identical in the remainder of the protein, including the RNP consensus motif domain and the glycine-rich domain characteristic of the mammalian A1 protein. We suggest that these sequence differences could affect the affinities of the proteins for RNA or other protein components of heterogeneous nuclear RNP complexes, leading to differences in function.

Age Factors↗
PubMed1989

The Drosophila fsh locus, a maternal effect homeotic gene, encodes apparent membrane proteins.

The maternal effect gene fsh is involved in the establishment of segments and the specification of their identities; the progeny of mutant females are missing portions of thoracic and abdominal segments, and may have homeotic transformations of third thoracic segments to second thoracic segments. The fsh locus interacts synergistically with loci such as Ubx and trx in the production of homeotic transformations. We have characterized cDNA clones corresponding to the major fsh transcripts expressed in ovaries and early embryos, and to a pupal transcript. The expression of fsh transcripts in ovaries is restricted to the germline; in developing embryos, transcripts are found throughout the cytoplasm. The different ovarian/embryonic transcripts (7.6 and 5.9 kb) are generated by use of alternative polyadenylation and splice sites. These transcripts encode two large predicted proteins of 110 and 205 kDa that have unusual amino acid compositions: 40% of the residues are glycine, alanine, or serine, and there are several regions of homopolymers and simple sequence repeats. Hydropathy analysis indicates that these proteins span the membrane. We suggest that the expression of fsh proteins in the membrane of the embryo is required for proper functioning of genes such as Ubx in the specification of segmental identity.

Amino Acid Sequence↗
PubMed1988

The lethal myospheroid gene of Drosophila encodes a membrane protein homologous to vertebrate integrin beta subunits.

A mutant of Drosophila melanogaster carrying the lethal(1) myospheroid mutation [l(1)mys] has a defective musculature and a phenotype that suggests a defect of basement membranes. The genomic region that is interrupted by an insertion in a mutant carrying l(1)mys was used to isolate cDNA clones, and their sequences are presented here. The cDNA sequence predicts a cysteine-rich integral membrane protein that displays 45% sequence identity to chicken integrin and the human fibronectin receptor beta subunit and much greater similarity over localized segments. These similarities extend to other vertebrate integrin beta subunits, and we conclude that the myospheroid protein is an integrin beta subunit of Drosophila. This implies evolutionary conservation of a group of transmembrane proteins that are receptors for extracellular matrix and, coupled with the myospheroid phenotype, indicates an important role for the interaction of cells with extracellular matrix during development.

Amino Acid Sequence↗
PubMed1987

A highly polymorphic region in the X chromosome of Drosophila.

Many cloned regions of the Drosophila genome show minimal variation between strains in overall sequence arrangement. While restriction site polymorphisms occur and the location of transposable elements may vary from one strain to another, such changes appear to be relatively minor variations superimposed on overall genome stability. In contrast to this general situation, we describe here a segment of the X chromosome that is highly polymorphic in four strains of D. melanogaster and in D. simulans. The strains differ in the presence and extent of a short duplication and the presence of repetitive DNA. These results suggest that different regions of the genome may be subject to different evolutionary constraints, with some regions being particularly prone to extensive changes, even within a single species.

Animals↗
PubMed1987

pen repeat sequences are GGN clusters and encode a glycine-rich domain in a Drosophila cDNA homologous to the rat helix destabilizing protein.

Several cDNA clones that contain the pen repeat have been isolated and sequenced; pen consists of clusters of GGN triplets, where N can be any nucleotide. Some of the pen repeat sequences are found within long open reading frames in which they encode oligoglycine stretches. For one of the clones, the deduced amino acid sequence of the entire open reading frame, especially in the region preceding the glycine-rich domain, shows strong homology to the rat helix destabilizing protein [Cobianchi, F., SenGupta, D. N., Zmudzka, B. Z. & Wilson, S. H. (1986) J. Biol. Chem. 261, 3536-3543]. The rat protein and homologs in other organisms are single-stranded nucleic acid binding proteins, some of which are major components of heterogeneous nuclear ribonucleoprotein particles. We suggest that we have cloned a cDNA encoding a Drosophila single-stranded nucleic acid binding protein.

Amino Acid Sequence↗
PubMed1986

Genetic and molecular analysis of fs(1)h, a maternal effect homeotic gene in Drosophila.

Mutations at the Drosophila melanogaster locus female sterile (1) homeotic (fs(1)h) result in segmental abnormalities including missing organs and homeotic transformations in the progeny of mutant mothers. Homeotic transformations are enhanced when the zygotes carry one of several third chromosome mutations, specifically alleles or deficiencies of the trithorax (trx) locus, also called Regulator-of-bithorax, and some alleles of bithorax complex (BX-C) genes. These observations suggest that maternally derived fs(1)h+ product is required, in interaction with trx and BX-C genes, for normal segment specification. The fs(1)h gene and an adjacent gene, lethal (1) myospheroid (l(1)mys), have been cloned by chromosomal walking. Mutations of fs(1)h were found within a 13-kb stretch of DNA. Poly(A)+ RNAs migrating as a doublet at 7.6 kb and a single band at 5.9 kb, which are homologous to the fs(1)h+ chromosomal region, are found in ovaries and early embryos. The largest RNAs are derived from a 20-kb chromosomal region encompassing the sites of all mapped fs(1)h alleles.

Alleles↗
PubMed1985

Gene expression in Xenopus embryogenesis.

This article considers some aspects of the storage of macromolecules in the oocyte of Xenopus laevis and the activation of previously unexpressed genes during early embryogenesis. The large quantity and complex nature of poly(A)+ RNA accumulated in the egg provides the cleavage embryo with a supply of mRNA sufficient to sustain protein synthesis for several hours of development. Onset of gene activity at the midblastula transition (MBT) leads to the synthesis and accumulation of molecules of various RNA classes, including tRNAs, rRNAs, mRNAs and mitochondrial RNAs. At gastrulation the poly(A)+ RNA population is still qualitatively similar to that of the egg but some sequences not present in egg RNA have accumulated by this time. Through the use of a subtractive cDNA cloning procedure we have prepared a library of sequences that represent genes activated for the first time between MBT and gastrula. A study of several of these cDNA clones suggests that genes in this class are restricted in their activity to embryonic and tadpole stages.

Animals↗