Cloning and expression of the human galanin receptor GalR2.

Galanin is a peptide hormone which modulates a wide variety of physiological processes, including secretion, muscle contraction, cognitive function, the reproductive axis, and feeding. Two galanin receptor subtypes, GalR1 and GalR2, have been cloned; however, for GalR2 only the rat sequence has been reported in the literature. Our cloning of human GalR2 reveals its amino acid sequence to be 85% identical to rat GalR2 and 39% identical to human GalR1. Binding of [125I]galanin to the human GalR2 receptor transiently expressed in COS-7 cells was saturable (Kd = 0.24 nM +/- 0.06 nM) with a receptor density of 383 +/- 66 fmol/mg protein. Human galanin(1-30) bound with high affinity to the human GalR2 receptor, with a Ki value of 0.86 +/- 0.12 nM. With the identification of a second galanin receptor subtype, the specific functions of human galanin receptor subtypes can now begin to be addressed.

Conversion of a silencer into an enhancer: evidence for a co-repressor in dorsal-mediated repression in Drosophila.

The dorsal (dl) protein gradient determines patterns of gene expression along the dorsal-ventral axis of the Drosophila embryo. dl protein is at peak levels in ventral nuclei of the embryo where it activates some genes (twist and snail) and represses others [zerknullt (zen), decapentaplegic and tolloid]. It is a member of the rel family of transcription factors and interacts with specific DNA sequences in the regulatory regions of its target genes. These sequences (dl binding sites), when taken from the context of either an activated or repressed promoter, mediate transcriptional activation of a heterologous promoter, but not repression. We found that T-rich sequences close to the dl binding sites in the silencer region of the zen promoter are conserved between three Drosophila species. Using this sequence information we defined a minimal element that can mediate repression of a heterologous promoter. This element interacts with at least two factors present in embryonic extracts, one of which is dl protein. The other factor binds to the T-rich site. Point mutations in either site abolish ventral repression in vivo. In addition, mutations in the T-rich site cause ectopic expression in ventral regions indicating that the minimal silencer was converted into an enhancer.

[Nucleotide sequence of the barley C-hordein gene]. / Nukleotidnaia posledovatel'nost' gena C-gordeina iachmenia.

The nucleotide sequence of barley C-hordein gene lambda CH4 and its flanking regions of 2820 bp length was determined. The gene contains no introns and codes for 310 amino acid long polypeptide. The 94% of the deduced amino acid sequence of the mature protein (291 amino acids) is made up of a repeating octapeptide motiff, PQQPEPQQ, which is repeated throughout the peptide chain between a unique 12 amino acid long NH2 terminal and a unique 6 amino acid long COOH-terminal end. In the 5' non-coding region there are TATA-, AGGA-, CAAT-and "endosperm" boxes. The 3' non-coding region has two polyadenylation signals. Compared with the published C-hordein sequences, our gene contains a number of insertions, deletions and substitutions. In the 3'-untranslated region there are two insertions 157 and 23 bp long. For the longer insertion no significant homology was found in the Gene Bank datebase. This insertion is the largest known rearrangement in the otherwise highly conservative surroundings of barley storage protein genes.