Demonstration by immunofluorescence of somatotropic cells and prolactin cells in the monkeys Erythrocebus patas, Cercopithecus aethiops and Papio hamadryas]

Using antibodies against human STH and ovine prolactine, it is possible to identify somatotropic and prolactin cells in the pituitary anterior lobe of three species of monkeys: Erythrocebus patas, Cercopithecus aethiops and Papio hamadryas. The somatotropic cells are numerous in both adult and infant male or female monkeys, especially in the lateral lobes of the pituitary gland. The prolactin cells can be distinguished in all pituitaries studied, regardless age or sex; indeed there are more numerous in adult females. The immunofluorescent technique reveals a more great number of cells of somatotropic and prolactin type than the classical tetrachrome technique.     

Optical microscopic study of the effect of the hypothalamic hormone T.R.H. on certain cell types of rat anterior hypophysis]

A cytological and optical microscopic study of the anterior lobe of hypohysis in the Wistar adult rat 10, 30 or 60 minutes after intravenous injection of 50 mug of synthetic TRH discloses modifications of thyrotropic cells and prolactin cells. It's possible to recognize a quick degranulation of the prolactin cells (with a maximum at the 10th minute) and a slower degranulation of the thyrotropic cells (perceptible at the 10th minute and very pronounced at the 60th minute). The somatrotopic cells did not show any modification.     

Identification of a potent MAR element from the mouse genome and assessment of its activity in stable and transient transfections

Matrix attachment regions are DNA sequences found throughout eukaryotic genomes that are believed to define boundaries interfacing heterochromatin and euchromatin domains, thereby acting as epigenetic regulators. When included in expression vectors, MARs can improve and sustain transgene expression, and a search for more potent novel elements is therefore actively pursued to further improve recombinant protein production. Here we describe the isolation of new MARs from the mouse genome using a modified in silico analysis. One of these MARs was found to be a powerful activator of transgene expression in stable transfections. Interestingly, this MAR also increased GFP and/or immunoglobulin expression from some but not all expression vectors in transient transfections. This effect was attributed to the presence or absence of elements on the vector backbone, providing an explanation for earlier discrepancies as to the ability of this class of elements to affect transgene expression under such conditions.     

The p24 family member p23 is required for early embryonic development

The p24 family of type I integral-membrane proteins, which are localised in the endoplasmic reticulum (ER), the intermediate compartment and the Golgi apparatus, are thought to function as receptors for cargo exit from the ER and in transport vesicle formation. Members of the p24 family have been found in a molecular complex and are enriched in COPI-coated vesicles, which are involved in membrane traffic between the ER and Golgi complex. Although expressed abundantly, simultaneous deletion of several family members does not appear to affect cell viability and protein secretion in yeast. In order to gain more insights into the physiological roles of different p24 proteins, we generated mice deficient in the expression of one family member, p23 (also called 24delta1, see for alternative nomenclature). In contrast to yeast genetics, in mice disruption of both p23 alleles resulted in early embryonic lethality. Inactivation of one allele led not only to reduced levels of p23 itself but also to reduced levels of other family members. The reduction in steady-state protein levels also induced structural changes in the Golgi apparatus, such as the formation of dilated saccules. The generation of mice deficient in p23 expression has revealed an essential and non-redundant role for p23 in the earliest stages of mammalian development. It has also provided genetic evidence for the participation of p24 family members in oligomeric complexes and indicates a structural role for these proteins in maintaining the integrity of the early secretory pathway.     

Imaging phosphorylation dynamics of the epidermal growth factor receptor

Epidermal growth factor receptor (EGFR) signaling is initiated by ligand binding followed by homodimerization and rapid receptor autophosphorylation. Monitoring EGFR phosphorylation was achieved by measuring translocation and binding of an enhanced yellow fluorescent protein (EYFP)-labeled phosphotyrosine-binding domain (PTB) to enhanced cyan fluorescent protein (ECFP)-tagged EGFR using fluorescence lifetime imaging microscopy or sensitized emission measurements. To simplify dynamic phosphorylation pattern measurements in cells, FLAME, a ratiometric sensor containing both EGFR-ECFP and PTB-EYFP in one molecule, was designed and examined in COS7 cells. Epidermal growth factor (EGF) treatment demonstrated rapid and reversible changes in the EYFP/ECFP fluorescence emission ratios, due to binding of the PTB domain to its consensus binding sites upon phosphorylation at the cell periphery, whereas perinuclear regions failed to respond to EGF but were responsive to tyrosine kinase inhibition. Long-term EGF treatment resulted in accumulation of dephosphorylated receptor in the perinuclear region due to active dephosphorylation occurring at intracellular sites. This indicates that the sensor closely approaches the true dynamics of tyrosine kinase autophosphorylation and dephosphorylation. Phosphatase inhibition by pervanadate resulted in an irreversible response in all cellular compartments. These data show that EGFR is under tonic phosphatase suppression maintaining the receptor in an unphosphorylated (silent) state and is dephosphorylated at endomembranes after ligand-mediated endocytosis.     

Immunocytochemical localization of protein S-100 in the retina of the monkey Macaca irus

Using an anti-human S-100 protein antibody, the Müller cells of the retina of the monkey Macacus irus were immunostained in the neural retina and in the ora serrata. In the anterior part of the retina (blind retina), all the cells were immunostained with the anti-S-100 protein antibody.