Bulletin of the Department of Agriculture, Jamaica.

3, 1905

Activation domain-mediated enhancement of activator binding to chromatin in mammalian cells.

DNA binding by transcriptional activators is typically an obligatory step in the activation of gene expression. Activator binding and subsequent steps in transcription are repressed by genomic chromatin. Studies in vitro have suggested that overcoming this repression is an important function of some activation domains. Here we provide quantitative in vivo evidence that the activation domain of GAL4-VP16 can increase the affinity of GAL4 for its binding site on genomic DNA in mammalian cells. Moreover, the VP16 activation domain has a much greater stimulatory effect on expression from a genomic reporter gene than on a transiently transfected reporter gene, where factor binding is more permissive. We found that not all activation domains showed a greater activation potential in a genomic context, suggesting that only some activation domains can function in vivo to alleviate the repressive effects of chromatin. These data demonstrate the importance of activation domains in relieving chromatin-mediated repression in vivo and suggest that one way they function is to increase binding of the activator itself.

Rat hippocampal neurons express genes for both rod retinal and olfactory cyclic nucleotide-gated channels: novel targets for cAMP/cGMP function.

Cyclic nucleotide-gated (CNG) channels are Ca(2+)-permeable, nonspecific cation channels that can be activated through direct interaction with cAMP and/or cGMP. Recent electrophysiological evidence for these channels in cultured hippocampal neurons prompted us to investigate the expression of CNG channel genes in hippocampus. PCR amplification detected the expression of transcripts for subunit 1 of both the rod photoreceptor (RCNGC1) and the olfactory receptor cell (OCNGC1) subtype of CNG channel in adult rat hippocampus. In situ hybridization detected expression of both channel subtypes in most principal neurons, including pyramidal cells of the CA1 through CA3 regions and granule cells of the dentate gyrus. From the hybridization patterns, we conclude that the two genes are colocalized in individual neurons. Comparison of the patterns of expression of type 1 cGMP-dependent protein kinase and the CNG channels suggests that hippocampal neurons can respond to changes in cGMP levels with both rapid changes in CNG channel activity and slower changes induced by phosphorylation. Future models of hippocampal function should include CNG channels and their effects on both electrical responses and intracellular Ca2+ levels.

III. Sermon notes, 1746-1747

This paper notebook contains abstracts of sermons attended between January 12, 1745/6 and November 15, 1747 in Kingston, Massachusetts, presumably by William Sever. The notebook lists the minister by last name, the location ("King." for Kingston), the date the sermon was delivered, the biblical passage used, and one-to-two-page entries on the sermon containing numbered notes and a section titled "Improvements and Applications." From the front of the volume, the pages contain entries for sermons attended between January 12 1745/6 through November 30, 1746, and there are no entries for June-September 1746. Sermon entries for December 7, 1746 to November 15, 1747 are written tête-bêche from the other end of the volume, and there are no entries for February-July 1747. Almost all of the sermons were delivered by Rev. William Rand, but there are sporadic sermons by additional ministers, who based on the last name are presumed to be John Angier (1701-1787; Harvard AB 1720), Ebenezer Gay (1696-1787; Harvard AB 1714), Nathaniel Eells (1678-1750; Harvard AB 1699), Josiah Torrey (1720-1783; Harvard AB 1741) and Daniel Shute (1722-1802; Harvard AB 1743).

Bulletin of the Department of Agriculture, Jamaica.

5-6, 1907-1908

Bulletin of the Department of Agriculture, Jamaica.

1, 1903