Gene isolation in Arabidopsis thaliana by conditional overexpression of cDNAs toxic to Saccharomyces cerevisiae: Identification of a novel early response zinc-finger gene
MOLECULAR & GENERAL GENETICS
Authors: MartinezGarcia, M; GarciduenasPina, C; Guzman, P
Abstract
In an effort to identify novel regulatory plant genes, conditional overexpression of toxic Arabidopsis thaliana gene products in Saccharomyces cerevisiae was evaluated as a genetic selection scheme. The screening method was tested on a fraction of a cDNA expression library and led to the identification of two Arabidopsis cDNA clones that were toxic to yeast; one corresponded to histone H1 and the other to a previously unidentified gene. This new gene, named ATL2, combines a RING-like zinc-binding motif and a putative signal anchor sequence for membrane insertion in the same molecule. Furthermore, inspection of the 3' untranslated region reveals two types of sequences which appear to be key determinants in rapid transcript decay. Indeed, rapid and transient accumulation of transcript occurs in the presence of a protein synthesis inhibitor and of the growth regulator auxin. These features provide evidence that ATL2 is an early-response gene. Thus, ATL2 represents one of the first early-response plant genes to be described which possesses a distinct regulatory domain; the fact that ATL2 mRNA is induced by auxin suggests that it might have a role during the response of plants to this growth regulator.
Global climate signals and equatorial SST variability in the Indian, Pacific and Atlantic oceans during the 20th century
GEOPHYSICAL RESEARCH LETTERS
Authors: Tourre, YM; White, WB
Abstract
Oceanic global and individual basin (i.e., Indian, Pacific and Atlantic oceans) sea surface temperature (SST) and sea level pressure (SLP) are analyzed jointly, using MTM/SVD technique. Besides global and individual secular variability, differences in low-frequency climate signals are evidenced: that is, an inter-decadal signal dominates in the Indian and Pacific oceans, while a quasi-decadal signal dominates in the Pacific and Atlantic oceans. Two inter-annual global and individual climate signals dominate: i.e., ENSO and quasi-biennial (QB). Moreover, significant correlations are found between three known equatorial SST indices (i.e., IO1 in Indian Ocean, NINO3 in Pacific Ocean, and ATL2 in Atlantic Ocean), and SST time-series obtained by summing-up only global lead-frequency signals identified here: i.e., 0.74, 0.82, and 0.56 respectively. These results should help improving long-term climate numerical forecasts and mitigating societal impacts by using observed specific equatorial SSTs time-series, in a climate change context.