We have analysed the promoter regions of two closely related auxin-regulated glutathione S-transferase genes. All active deletion constructs tested showed expression of the reporter gene beta-glucuronidase (gusA) in root tips of young seedlings and newly developing lateral roots. Auxin treatment greatly enhanced the level of expression. The Nt103-1 promoter region -370/-276 was found to be necessary, at least as a quantitative element to confer auxin-responsiveness to a reporter gene, and sequences responsible for the auxin-responsiveness must be located downstream of -370. The region -651/-370 contains sequence information necessary for uninduced expression. The Nt103-35 promoter manifested its auxin-responsiveness within the -504/-310 region. Electrophoretic mobility shift analysis, using nuclear extracts from tobacco leaves and suspension cells, identified a factor binding to a sequence (ap103, TGAGTCT) at position -560 of the Nt103-1 promoter, which shows homology to the mammalian AP-1 site. A second factor was found to bind a sequence (as103, ATAGCTAAGTGCTTACG) with homology to the CaMV 35S promoter as-1 element. The as103 element is present in both promoters and positioned around -360, so within the region determined to be indispensable for the response to auxin. A third factor was found binding to the -276/-190 region of both promoters. Combined, these data point to the relevance of a 90 bp region for auxin-induced activity of both tobacco genes. The ASF-1 like factor binding to the as103 element within this region might be involved in mediating the auxin response.

development in the ,field of monolithic integrated circuits. At present Argentina, in 1970. he is Head of a Digitaf DesignGroup there. While at the University of Cordoba, he was engaged in research on system automation. From 1970 to 1971he wasemployed at Lennox, Cordoba, as a Development En@eer in industrial electronics and system automation, He Geoffrey W. Sumerling, for a photograph and biography, seethis issue, was with Philips, Eindhoven, The Netherlands, p. 127.

Abstract-The complexes [CrNCS(H20)5] 2+, [CrCI(H20)s] ~+, [CrF(H20)~, 2+ and [Cr(H20)6] a+ were studied by polarography and cyclic voltammetry in aqueous solution. It is shown that Triton X-100 and gelatine shift the polarographic waves to more negative potentials. In 1M NaCIO4-HCIO4 the half-wave potentials in the absence of maximum suppressor are (in Volts vs. SCE): CrNCS2+: --0.675; CrCI2+: -0.62; CrF~+:-1.105; Cr3+: -0.90 (water omitted in the formula). All reductions are irreversible. Replacement of NaC104 by NaSCN makes the reduction of CrNCS 2+ and CrCI z+ more reversible and shifts E½ 50 mV per log [SCN-I unit to more negative potentials for CrNCS z+ and 66 mV for CrCI 2+. It is suggested that CrNCS 2+ and CrCI 2+ may be reduced via a mecbanism analogous to the inner-sphere mechanism in homogeneous reductions.

An MOS transistor is described in which the source and drain areas are obtained by diffusion from doped polycrystalline silicon. Polysilicon tracks form the interconnect with the diffusion areas without the need for contact windows. As a result trarnsistor and junction sizes are reduced by a factor 2 or 3 over a normal structure. Polycrystalline silicon tracks in this

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