U2AF homology motifs: protein recognition in the RRM world

Recent structures of the heterodimeric splicing factor U2 snRNP auxiliary factor (U2AF) have revealed two unexpected examples of RNA recognition motif (RRM)-like domains with specialized features for protein recognition. These unusual RRMs, called U2AF homology motifs (UHMs), represent a novel class of protein recognition motifs. Defining a set of rules to distinguish traditional RRMs from UHMs is key to identifying novel UHM family members. Here we review the critical sequence features necessary to mediate protein-UHM interactions, and perform comprehensive database searches to identify new members of the UHM family. The resulting implications for the functional and evolutionary relationships among candidate UHM family members are discussed.     

Erythrocyte transketolase activity in patients with chronic renal disease

B1 vitamin deficiency was studied by the erythrocyte enzyme activation test in patients with chronic uraemia. Transketolase activity was measured in the erythrocyte haemolysates of 14 patients with chronic uraemia and in 16 healthy controls in the presence of TPP and following TPP saturation. The magnitude of activity increases as a result of TPP saturation which is probably indicative of an insignificant thiamine deficiency in patients with chronic uraemia.     

An ordered comparative map of the cattle and human genomes

A cattle-human whole-genome comparative map was constructed using parallel radiation hybrid (RH) mapping in conjunction with EST sequencing, database mining for unmapped cattle genes, and a predictive bioinformatics approach (COMPASS) for targeting specific homologous regions. A total of 768 genes were placed on the RH map in addition to 319 microsatellites used as anchor markers. Of these, 638 had human orthologs with mapping data, thus permitting construction of an ordered comparative map. The large number of ordered loci revealed > or =105 conserved segments between the two genomes. The comparative map suggests that 41 translocation events, a minimum of 54 internal rearrangements, and repositioning of all but one centromere can account for the observed organizations of the cattle and human genomes. In addition, the COMPASS in silico mapping tool was shown to be 95% accurate in its ability to predict cattle chromosome location from random sequence data, demonstrating this tool to be valuable for efficient targeting of specific regions for detailed mapping. The comparative map generated will be a cornerstone for elucidating mammalian chromosome phylogeny and the identification of genes of agricultural importance."Ought we, for instance, to begin by discussing each separate species-in virtue of some common element of their nature, and proceed from this as a basis for the consideration of them separately?" from Aristotle, On the Parts of Animals, 350 B.C.E.     

Human mini-chromosomes in mouse embryonal stem cells

We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb in size into mouse embryonal stem cells. Although these human mini- chromosomes are stable in hamster and chicken cells, they re-arrange or segregate aberrantly in the embryonal stem cells and are rapidly lost in the absence of selection. However, one of the mini-chromosomes re- arranged, acquired mouse centromeric sequences and was then stably maintained for at least 60 population doublings in culture. This mini- chromosome, which is 4 Mb in size, is a candidate for a mouse germ line chromosome vector.      

An interactive, microcomputer-based karyotype analysis system for phylogenetic cytotaxonomy

A versatile and practical semi-automatic computerized system of karyotype analysis has been developed for phylogenetic cytotaxonomy for under $4,000. The modular software system is designed for use solely with a small 8-bit microcomputer and requires virtually no custom made hardware. The system interacts with the operator and greatly augments the speed and accuracy of cytotaxonomic investigations.     

Aspartylglucosaminuria in the United States

Aspartylglucosaminuria (AGU) was diagnosed in two unrelated males with progressive mental retardation, coarse facies and skeletal abnormalities. Until now, this disorder has been described in predominantly Finnish populations with only one previous case reported in the U.S. We conclude that AGU may be more common in nowFinnish populations than the number of reported cases would indicate and should be included in the differential diagnosis in patients with suspected lysosomal storage disorders regardless of their geographical or ethnic backgrounds.     

Foetal placental blood flow in the lamb

1. Fifteen sheep foetuses of 1.5-5.2 kg body weight were prepared with indwelling arterial and venous catheters for experimentation one to six days later.2. Unanaesthetized foetuses were found to have mean arterial and central venous blood pressures of 40 +/- 1.5 (S.E. of mean) and 2.0 +/- 0.3 (S.E. of mean) mm Hg respectively, compared to intra-uterine pressure. Intra-uterine pressure was 16 +/- 0.8 (S.E. of mean) mm Hg with respect to atmospheric pressure at mid-uterine level.3. Mean placental blood flow of the foetuses was 199 +/- 20 (S.E. of mean) ml./(min.kg body wt.). Mean cardiac output in eleven of the foetuses was 658 +/- 102 (S.E. of mean) ml./(min.kg).4. Mean foetal and maternal colloid osmotic pressures were 17.5 +/- 0.7 (S.E. of mean) and 20.5 +/- 0.6 (S.E. of mean) mm Hg respectively at 38 degrees C.5. Intravenous infusions into six ewes of 1.8 mole of mannitol and 0.4 mole of NaCl resulted in significant increases in foetal plasma osmolarity, sodium, potassium, and haemoglobin concentrations, without detectable transfer of mannitol to the foetal circulation.6. In the sheep placenta there is osmotic and hydrostatic equilibration of water. As a consequence, there should be an interaction between foetal placental blood flow and foetal water exchange with the maternal circulation. It was concluded that this interaction tends to stabilize foetal placental blood flow.     

Persistence and amplification of St. Louis encephalitis virus in the Coachella Valley of California, 2000-2001

The introduction of a St. Louis encephalitis virus (SLE) genotype new to southeastern California during 2000 was followed by focal enzootic amplification in the Coachella Valley that was detected by seroconversions of 29 sentinel chickens in five of nine flocks of 10 chickens each, isolations of virus from 30 of 538 pools of 50 Culex tarsalis Coquillett females, and collection of 30 positive sera from 2,205 wild birds. This SLE strain over wintered successfully and then amplified during the summer of 2001, with 47 sentinel seroconversions in eight of nine flocks, 70 virus isolations from 719 pools of Cx. tarsalis and Cx. p. quinquefasciatus Say, and 40 positive sera from 847 wild birds. Human illness was not detected by passive case surveillance, despite issuance of a health alert during 2001. Virus amplification during both years was associated with above average temperatures conducive for extrinsic incubation and below average precipitation during spring associated with below average vector abundance. Seroconversions by sentinel chickens provided the timely detection of virus activity, with initial conversions detected before positive mosquito pools or wild bird infections. Vertical infection was not detected among Cx. tarsalis adults reared from immatures collected during the fall-winter of 2000, even though SLE over wintered successfully in this area. Early seroconversions by a sentinel chicken during February 2001 and a recaptured Gambel's quail in April 2001 provided evidence for transmission during winter and spring when ambient temperatures averaged below 17 degrees C, the threshold for SLE replication.