By using chloramphenicol acetyltransferase (CAT) assays in neuron-derived cell lines, we show here that promoter activity associated with the herpes simplex virus type 1 latency-associated transcript (LAT) had neuronal specificity. Promoter activity in these transient CAT assays coincided with a DNA region containing excellent RNA polymerase II promoter consensus sequences. Primer extension analysis in a LAT promoter-CAT plasmid construct placed the start of transcription about 28 nucleotides from the first T in the consensus TATA box sequence. Neuronal specificity of this promoter was suggested by examining the effect of sequences upstream of the promoter on CAT activity in neuronal versus nonneuronal cells. In nonneuronal cells, promoter activity was decreased 3to 12-fold with the addition of upstream sequences. In contrast, in neuron-derived cells, the addition of upstream sequences did not decrease promoter activity. The LAT promoter predicted by our transient CAT assays was located over 660 nucleotides upstream from the 5' end of the previously mapped 2-kilobase (kb) LAT. This unusual location was explained by in situ and Northern (RNA) blot hybridization analyses that suggested that LAT transcription began near the promoter detected in our CAT assays, rather than near the 5' end of the 2-kb LAT. In situ hybridization with neurons from latently infected rabbits detected small amounts of LAT RNA within 30 nucleotides of the consensus TATA box sequence. This suggested that LAT transcription began near this TATA box. Northern blot hybridization of RNA from ganglia of latently infected rabbits revealed a faint 8.3-kb band of the same sense as LAT. We conclude that (i) the LAT promoter has neuronal specificity, (ii) the LAT promoter is located over 660 nucleotides upstream of the 5' end of the previously characterized stable 2-kb LAT, (iii) LAT transcription begins about 28 nucleotides from the first T of the consensus TATA box sequence and extends to near the first available polyadenylation site approximately 8.3 kb away, and (iv) this 8.3-kb RNA may be an unstable precursor of the more stable 2and 1.3-kb LATs.
Seaweeds, an integral part of marine coastal environment, are an important food, industrial raw materials and biostimulants for crop growth due to the presence of a number of plant growth stimulants. The sap of an economically important seaweed Kappaphycus alvarezii (K-sap) is gaining momentum for sustainable intensification of agricultural productivity. In the present study, the phytohormone levels and transcript regulation of defence-related genes were studied in tomato seedlings in response to K-sap application alone and in combination with the fungus Macrophomina phaseolina, the causal agent of charcoal rot in tomato. The application of Ksap alone and in combination with fungus M. phaseolina significantly increased the concentration of ABA, IAA, SA and zeatin hormones. The enhanced transcript of pathogenesis related genes (PR-1b1, PR-3 and PR-5) was observed in response to application of K-sap alone and in combination with fungus M. phaseolina in tomato. The transcription factor, Pti4 and mitogen-activated kinase pathway gene, MPK2 also showed transcript accumulation on combined treatment of Macrophomina and K-sap. This is the first report highlighting the differential regulation of defence-related genes in accordance with phytohormone levels on application of seaweed sap.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.