[Prognosis of affinity change of the TATA-binding protein to TATA-boxes upon polymorphisms of the human gene promoter TATA boxes].

TATA-binding protein (TBP) is a subunit of basal transcription factor TFIID that recognizes and binds to the TATA-box on TATA-containing promoters of class II genes, and starts assembling RNA polymerase II basal transcription complex. It is shown in many works that the sequence of TATA-box with its flanking regions affects the level of basal and activated transcription. TATA-box polymorphisms and human hereditary diseases associated with them show that TBP/TATA interaction may indirectly affect gene regulation in vivo. The object of this work is to determine changes in the TBP/TATA affinity upon polymorphisms in TATA-boxes of human gene promoters. We assess changes in TBP/TATA affinities in silico by using our formula of equilibrium TBP/TATA binding upon four consecutive steps: nonspecific binding <--> sliding <--> braking (stopping) <--> stabilization. Our prognoses agree with known examples of TATA-box polymorphisms and human hereditary diseases associated with them.

TATA box polymorphisms in human gene promoters and associated hereditary pathologies.

TATA-binding protein (TBP) is the first basal factor that recognizes and binds a TATA box on TATA-containing gene promoters transcribed by RNA polymerase II. Data available in the literature are indicative of admissible variability of the TATA box. The TATA box flanking sequences can influence TBP affinity as well as the level of basal and activated transcription. The possibility of mediated involvement in in vivo gene expression regulation of the TBP interactions with variant TATA boxes is supported by data on TATA box polymorphisms and associated human hereditary pathologies. A table containing data on TATA element polymorphisms in human gene promoters (about 40 mutations have been described), associated with particular pathologies, their short functional characteristics, and manifestation mechanisms of TATA-box SNPs is presented. Four classes of polymorphisms are considered: TATA box polymorphisms that weaken and enhance promoter, polymorphisms causing TATA box emergence and disappearance, and human virus TATA box polymorphisms. The described examples are indicative of the polymorphism-associated severe pathologies like thalassemia, the increased risk of hepatocellular carcinoma, sensitivity to H. pylori infection, oral cavity and lung cancers, arterial hypertension, etc.

Increased interaction of proteins in nuclear extract from mouse liver and lung tumors with TATA-containing oligonucleotide.

Increased TATA-binding activity of proteins in nuclear extracts from murine hepatocarcinoma HA-1 and murine Lewis lung adenocarcinoma was demonstrated. The dependence of the amount of formed complexes on protein concentration, displacement of labeled 32P-TATA-containing oligonucleotide by its unlabeled analog, and weak interaction with an oligonucleotide containing damaged TATA box confirm specificity of the formed complexes.

[Interaction of proteins from general transcription complex RNA polymerase II with oligoribonucleotides].

We have analyzed an interaction of the general transcription complex RNA polymerase II proteins (RNA polymerase II, factors TBP, TFIIB, TFIIF, TFIIE and TFIIH) S. cerevisiae with the oligoribonucleotides. With the help of method EMSA was shown that labeled 32P labeled oligoribonucleotide 5'-ACUCUCUUCCGCAUCGC-3' (r-17) binds with the proteins and generates three species of the complexes with the three major shifts. All the three species of the complexes are RNA specific because a total RNA S. cerevisiae was a competitor for all three species but the TATA-containing oligodeoxyribonucleotide (500-fold molar excess) was not a competitor for its. Complexes 32P-r-17 with the proteins belonging to the middle shift are the sequence specific because unlabeled r-17 was a competitor for its binding (100-fold molar excess) but unlabeled UA-rich oligoribonucleotide (5'-AUAUUAUGUUCAAAA-3) was not a competitor for this shift (500-fold molar excess). Complexes belonging to the upper shift are RNA specific probably. We think 32P-r-17 interaction with the proteins belonging to the under shift is nonspecific corresponding to a sorbtion of 32P-r-17 on a protein. The data presented demonstrate that oligoribonucleotide and oligodeoxyribonucleotide don't compete for the binding sites on a basal transcription complex proteins.