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Exendin-4 purified from Heloderma suspectum venom shows structural relationship to the important incretin hormone glucagon-like peptide 1-(7-36)-amide (GLP-1). We demonstrate that exendin-4 and truncated exendin-(9-39)-amide specifically interact with the GLP-1 receptor on insulinoma-derived cells and on lung membranes. Exendin-4 displaced 125I-GLP-1, and(More)
Activation of osteoclasts and their acidification-dependent resorption of bone is thought to maintain proper serum calcium levels. Here we show that osteoclast dysfunction alone does not generally affect calcium homeostasis. Indeed, mice deficient in Src, encoding a tyrosine kinase critical for osteoclast activity, show signs of osteopetrosis, but without(More)
An improved vector system has been developed for the in vitro construction of transcriptional fusions to lacZ. The principal feature is an RNaseIII cleavage site inserted between the polylinker cloning site and the promoterless lacZ gene. When these vectors are used to construct transcriptional fusions, the subsequent cleavage of the hybrid mRNA at the(More)
The binding of the Ca2+-channel blocker d-cis-[3H]diltiazem to guinea pig skeletal muscle microsomes is temperature-dependent. At 2 degrees C the KD is 39 nM and Bmax is 11 pmol/mg protein. The binding is fully reversible (K -1 = 0.02 min -1). The binding sites discriminate between the diastereoisomers l- and d-cis-diltiazem, reconize verapamil, gallopamil(More)
The genes for the beta (rpoB) and beta' (rpoC) subunits of Escherichia coli RNA polymerase are the distal members of a complex transcriptional unit that contains four upstream ribosomal protein genes. The RNA polymerase subunit genes are transcribed at a lower frequency than the ribosomal protein genes as a result of termination at an attenuator preceding(More)
The pattern of transcription of the rplKAJLrpoBC gene cluster of Escherichia coli appears to be complex. At least four different promoters and a transcriptional attenuator have been identified. To compare the relative effect of each of the putative promoters and the attenuator on transcription of these genes, we fused these regulatory sites to lacZ. These(More)
Expression of the rpoBC genes encoding the beta and beta' RNA polymerase subunits of Escherichia coli is autogenously regulated. Although previous studies have demonstrated a post-transcriptional feedback mechanism, complex transcriptional controls of rpoBC expression may also contribute. We show that an attenuator (rpoBa) separating the ribosomal protein(More)
Tritiated 1,4-dihydropyridines (nimodipine, nitrendipine, nifedipine, PN 200-110) and [3H]D-cis-diltiazem as well as [3H]verapamil were employed to directly identify calcium channels in membranes for excitable tissues. The channels, when probed with 1,4-dihydropyridines, exhibit the following properties: 1,4-Dihydropyridine calcium channel blockers bind in(More)
In order to delineate the region involved in feedback regulation of the RNA polymerase beta subunit (encoded by rpoB), a collection of rpoB-lacZ translational fusions with different endpoints both upstream and downstream of the rpoB start site was assembled on lambda phage vectors. The extent of translational repression of beta was monitored by measuring(More)