Isoprenylation of proteins: what is its role?]

The role of mevalonate in the control of DNA synthesis during the cell cycle has been studied and has lead to the detection of isoprenylated proteins. These proteins are modified by a polyisoprenoid (farnesyl or geranylgeranyl) moiety via a thioether linkage. This modification is required for the following steps of the post-translational maturation of these proteins: proteolysis of the last three C-terminal amino-acids and carboxymethylation of the Cysteine-COOH. The isoprenylation could play a role in the membrane localisation of these proteins. Farnesylated proteins present a C-terminal CAAX domain. Moreover, the farnesylation is required for their biological activity independently of the membrane localization (Prelamine A, p21ras(Val 12)). Among geranylgeranyl proteins, two types of C-terminal sequences have been found: one with the motif CAAX, the other with the motif CC or CXC. In the last type, both Cysteines are geranylgeranylated. The hydrophobicity of the geranylgeranyl moiety leads to the membrane attachment, without any specificity. Moreover, geranylgeranylation as well as farnesylation seem important for protein-protein interactions. Among the identified isoprenylated proteins, the lamins, gamma-subunits of G proteins and the numerous (if not all) members of the Ras superfamily were characterized. The exact role of isoprenylation is still uncertain but it seems to affect the membrane localization and the protein-protein interactions.     

Teratogenic effect of AY 9944 in rats: importance of the day of administration and maternal plasma cholesterol level

An inhibitor of cholesterol synthesis, AY 9944 (trans-1,4-bis(2-chlorobenzylaminomethyl) cyclohexane dihydrochloride) is teratogenic. A single dose of AY 9944 (50 mg/kg or 75 mg/kg) given to Wistar pregnant rats on the second, fourth, sixth, seventh, or eighth day of gestation induced malformations such as holoprosencephaly. They were often limited to isolated pituitary agenesis. The highest percentage of holoprosencephalic fetuses was found when AY 9944 was given on the fourth day of gestation. Whatever the dose and the day of administration, the lower the maternal plasma cholesterol level, the more frequent were holoprosencephalic fetuses. Therefore, it is suggested that the decrease in maternal plasma cholesterol level is at least one of the factors provoking holoprosencephaly.     

Effects of AY 9944 on low density lipoprotein metabolism in cultured human fibroblasts

Treatment of cultured human fibroblasts with the hypocholesterolemic drug AY 9944 resulted in a marked increase in low density lipoprotein internalization and degradation for concentrations up to 5 X 10(-6)M. Low density lipoprotein binding was less affected. Concentrations above 5 X 10(-6)M resulted in a relative decrease in low density lipoprotein degradation, whereas binding and internalization plateaued. The stimulation of low density lipoprotein internalization took place within the first hours of incubation of cells with the drug, which suggests a direct effect on the cell membrane. Such phenomenon could account at least partially for the hypocholesterolemic effect of the drug, besides its inhibitory effect on 7-dehydrocholesterol reductase.     

Computational analysis of small RNA cloning data

Cloning and sequencing is the method of choice for small regulatory RNA identification. Using deep sequencing technologies one can now obtain up to a billion nucleotides--and tens of millions of small RNAs--from a single library. Careful computational analyses of such libraries enabled the discovery of miRNAs, rasiRNAs, piRNAs, and 21U RNAs. Given the large number of sequences that can be obtained from each individual sample, deep sequencing may soon become an alternative to oligonucleotide microarray technology for mRNA expression profiling. In this report we present the methods that we developed for the annotation and expression profiling of small RNAs obtained through large-scale sequencing. These include a fast algorithm for finding nearly perfect matches of small RNAs in sequence databases, a web-accessible software system for the annotation of small RNA libraries, and a Bayesian method for comparing small RNA expression across samples.     

A reference-quality,fully annotated genome from a Puerto Rican individual

Until 2019, the human genome was available in only one fully annotated version, GRCh38, which was the result of 18 years of continuous improvement and revision. Despite dramatic improvements in sequencing technology, no other genome was available as an annotated reference until 2019, when the genome of an Ashkenazi individual, Ash1, was released. In this study, we describe the assembly and annotation of a second individual genome, from a Puerto Rican individual whose DNA was collected as part of the Human Pangenome project. The new genome, called PR1, is the first true reference genome created from an individual of African descent. Due to recent improvements in both sequencing and assembly technology, and particularly to the use of the recently completed CHM13 human genome as a guide to assembly, PR1 is more complete and more contiguous than either GRCh38 or Ash1. Annotation revealed 37,755 genes (of which 19,999 are protein coding), including 12 additional gene copies that are present in PR1 and missing from CHM13. Fifty-seven genes have fewer copies in PR1 than in CHM13, 9 map only partially, and 3 genes (all noncoding) from CHM13 are entirely missing from PR1.     

End-of-life modelling of buildings to support more informed decisions towards achieving circular economy targets

The International Journal of Life Cycle Assessment - Life cycle assessment (LCA) is an internationally accepted method to assess the environmental impacts of buildings. A major methodological...     

Carbonic anhydrases: hematologic relevance and a biosensing perspective

Carbonic anhydrases were first identified in red blood cells and have been thus traditionally addressed in a hematological context. However, recently there has been a shift of research interest to therapeutic areas, notably in solid cancers, relegating the impact of carbonic anhydrase function and pathological dysfunction in blood related physiology to secondary importance. This review addresses this paradigm and emphasizes the potential impact of recent studies on blood related carbonic anhydrase isotype expression and modulation in diverse areas such as physiology and pathology, biosensing, their use as biomarkers, and in the development of synthetic blood. A special emphasis is placed on reviewing new dynamic and quantitative studies that allow for the efficient tracking and quantitation of various carbonic anhydrase isozymes within the blood and more generally within the human body, that give new perspectives on the biochemical and physiological role of blood associated carbonic anhydrase in health and pathology.