Sequence tracts

Fig. 4.8. ITS2 folding of Schistosoma mansoni (U22168) based largely on Morgan and Blair (1998) and showing the four domains, A-D. Bases conserved in domains A and B across all 42 sequences from trematodes of eight families studied by Morgan and Blair (1998) are indicated (white letters on black circles). Lines along parts of domains B and C indicate the position of semi-conserved sequence tracts (see text).

The POMC gene is expressed in the anterior and intermediate lobes of the pituitary. The most conserved sequences between species are within the amino terminal fragment, the ACTH region, and the (3-endorphin region. POMC or related products are found in several other vertebrate tissues, including the brain, placenta, gastrointestinal tract, reproductive tract, lung, and lymphocytes. 

The ontogenesis of the AOS then, is closely bound up with the formation of its principal connection site within the mature brain. The sequence of events in mammals is revealed as a process which involves (1) early specialisation of presumptive GnRH cells (2) their attachment to and movement along specific (and transient) axonal bundles of the VN and N. terminalis tracts, and (3) coalescence of the neurocrine cells in the hypothalamus, where they complete differentiation as multi-axonal neurocrine cells. 

In this work we will focus on the use of the cubic phase as a delivery system for oligopeptides - Desmopressin, Lysine Vasopressin, Somatostatin and the Renin inhibitor H214/03. The amino acid sequences of these peptides are given in Table I. The work focuses on the cubic phase as a subcutaneous or intramuscular depot for extended release of peptide drugs, and as a vehicle for peptide uptake in the Gl-tract. Several examples of how the peptide drugs interact with this lipid-water system will be given in terms of phase behaviour, peptide self-diffusion, in vitro and in vivo release kinetics, and the ability of the cubic phase to protect peptides from enzymatic degradation in vitro. Part of this work has been described elsewhere (4-6). 

TES-32 is the most abundant single protein product secreted by the parasite. It is also heavily labelled by surface iodination of live larvae (Maizels et al., 1984, 1987), and is known by monoclonal antibody reactivity to be expressed in the cuticular matrix of the larval parasite (Page et al, 1992a). TES-32 was cloned by matching peptide sequence derived from gel-purified protein to an expressed sequence tag (EST) dataset of randomly selected clones from a larval cDNA library (Loukas et al., 1999). Because of the high level of expression of TES-32 mRNA, clones encoding this protein were repeatedly sequenced and deposited in the dataset (Tetteh et al., 1999). Full sequence determination showed a major domain with similarity to mammalian C-type (calcium-dependent) lectins (C-TLs), together with shorter N-terminal tracts rich in cysteine and threonine residues. Native TES-32 was then shown to bind to immobilized monosaccharides in a calcium-dependent manner (Loukas et al., 1999). 

Another type of intestinal peptide transporter, hPTl, which is significantly different in sequence from PEPT1, was identified using a functionally inhibitory monoclonal antibody [99]. This transporter is widely expressed in the human GI tract and facilitates the oral absorption of pdactam antibiotics and ACE inhibitors from the intestine [18, 99]. Interestingly, we recently reported that hPTl gene expression is approximately 4-fold higher than PEPT1 in the human duodenum [4] (Fig. 11.1). 

Degradation of 5 -terminal sequences in luciferase mRNA containing 60-nt poly(A) tract and capped with the indicated anti reverse cap analogs. The mRNAs half-lives were determined by real time PCR with primers directed against the 5 -end of luciferase mRNA as described in the text. 

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