Disease relevance of lacS

• After transformation of a S. solfataricus pyrEF/lacS double mutant, the vector was found to reside as a single-copy vector, stably integrated into the host chromosome via the site-specific recombination system of SSV1 [1].
• PCR, Southern blot analysis, comparative heterologous expression in Escherichia coli, and DNA sequence analysis excluded cis-acting mutations as the explanation for reduced lacS expression in group I mutants [2].

Psychiatry related information on lacS

• Culture conditions precipitating rapid changes in lacS gene expression were established to determine the response time of the regulatory system in vivo [3].

High impact information on lacS

• Greatly increased levels of lacS mRNA were detected in Northern analyses, demonstrating that this reporter gene system is suitable for the study of regulated promoters in Sulfolobus and that the vector can also be used for the high-level expression of genes from hyperthermophilic archaea [1].
• Expression of a promoter fusion between lacS and the car-independent malA promoter integrated either at amyA or at the natural lacS locus was insensitive to the allelic state of car [4].
• Despite gene overlap, expression of the lacS promoter proximal gene, SSO3017, exhibited coregulation but not cotranscription with lacS [4].
• In contrast, regulation of lacS by the car mutation was dependent on sequences upstream of the archaeal TATA box [4].
• In order to complement the LacS(-) phenotype, an expression vector was constructed by inserting the lacS coding sequence with its 5' and 3' flanking regions into the pEXSs plasmid [5].

Biological context of lacS

• The substrate specificity of the thermophilic beta-glycosidase (lacS) from the archaeon Sulfolobus solfataricus (SSbetaG), a member of the glycohydrolase family 1, has been analysed at a molecular level using predictions from known protein sequences and structures and through site-directed mutagenesis [6].
• The aa composition of the enzyme and, in particular, its peculiarly low cysteine content (one Cys per subunit) has been confirmed; at the same time, it has been observed that the very low G + C content of the S. solfataricus genome strongly influences the codon usage preferences in the lacS sequence [7].
• In fact, a derivative plasmid carrying an expression cassette of the lacS gene encoding the beta-glycosidase from S.solfataricus under the control of the Sulfolobus chaperonine (thermosome tf55) heat shock promoter was also able to drive the expression of a functional enzyme [8].

Associations of lacS with chemical compounds

• Complementation of the beta-galactosidase deficiency in a deletion mutant strain of S.solfataricus demonstrated that lacS gene was an efficient marker for selection of single transformants on solid minimal lactose medium [8].

Analytical, diagnostic and therapeutic context of lacS

• Northern blot analysis of malA and lacS mRNAs revealed that changes in enzyme abundance arose primarily from reductions in transcript concentrations [3].

References