Hindawi Publishing Corporation BioMed Research International Volume 2013, Article ID 413450, 6 pages http://dx.doi.org/10.1155/2013/413450 Research Article Transcription Regulation of Plastid Genes Involved in Sulfate Transport in Viridiplantae Vassily A. Lyubetsky, Alexander V. Seliverstov, and Oleg A. Zverkov Institute for Information Transmission Problems (Kharkevich Institute), he Russian Academy of Sciences, Moscow 127994, Russia Correspondence should be addressed to Vassily A. Lyubetsky; lyubetsk@iitp.ru Received 1 April 2013; Accepted 12 June 2013 Academic Editor: William Piel Copyright © 2013 Vassily A. Lyubetsky et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. his study considers transcription regulation of plastid genes involved in sulfate transport in the parasites of invertebrate (Helicosporidium sp.) and other species of the Viridiplantae. A one-box conserved motif with the consensus TAAWATGATT is found near promoters upstream the cysT and cysA genes in many species. In certain cases, the motif is repeated two or three times. 1. Introduction his study focuses on selected species of the Viridiplantae, particularly, the genus Helicosporidium sp. (class Trebouxio- phyceae), which comprises green algae parasitizing lies of the species Simulium jonesi [1–3]. Plastids of these parasites are a good target for antibiotic treatment, as earlier was shown for apicomplexan parasites of vertebrates (Toxoplasma gondii and Plasmodium spp. [4]). he plastome of Helicosporidium sp. is relatively small, about 37 kb. Most of the plastome genes encode tRNA, rRNA, ribosomal proteins, and subunits of the bacterial-type RNA polymerase. One of two nonhousekeeping proteins is the CysT subunit of a sulfate ABC transporter. Sulfate ABC transporters in cyanobacteria and proteo- bacteria consist of two identical ATP-binding CysA pro- teins, two transmembrane proteins (CysT and CysW), and a sulfate-binding protein SbpA. In the cyanobacteria Syne- chocystis sp. PCC 6803 [5], genes encoding the sulfate trans- porter subunits are arranged in a single operon sbpA-ssr2439- cysT-cysW-cysA. In cyanobacteria, no data on expression is available for this operon; however, in Escherichia coli and some other proteobacteria, genes of the sulfate transporter subunits are known to be regulated in the single operon cysPTWAM (further details are given in Discussion). Plastomes of vascular plants lack genes of the sulfate transport system except for rare instances of cysT and cysA. However, the green alga Helicosporidium sp. retains cysT. Plastomes of the rhodophyte Cyanidium caldarium and Cyanidioschyzon merolae and the cyanelle genome of Cyanophora paradoxa lack cysT homologues but possess distant homologues of cysA presumably involved in the transport of zinc or manganese (further details are given in Results). Similar proteins are involved in the transport of molybdenum, zinc, and manganese and belong to a large family of transporters of ions, sugars, peptides, and more complex organic molecules. For example, the transcription regulation of the ziaA gene (encoding a polypeptide similar to a P-type ATPases involved in transporting heavy metals) is described in the cyanobacterium Synechocystis PCC 6803 [6]. he sulfate transport in plastids is necessary for the syn- thesis of many sulfur-containing compounds. For example, in Spinacia oleracea, the lack of sulfates leads to considerable changes in the expression of cysteine synthesis genes [7]. Also, plastids of many algae synthesize thiamine and other sulfur-containing compounds. For example, the lipoic acid is synthesized in plastids of apicomplexan parasites [8]. In this paper, we consider the expression regulation of cysT and cysA in Viridiplantae, in particular, Helicosporidium sp. and Pycnococcus provasolii, where cysT is present and cysA is absent. In proteobacteria, the regulation mechanism of tran- scription initiation of cysA and cysT is known. he CysB protein is a transcription factor of the LysR family and acts as a tetramer. his protein binds DNA upstream the −35 box of a promoter and activates transcription initiation of