Role of Mod(mdg4)-67.2 Protein in Interactions between Su(Hw)-Dependent Complexes and Their Recruitment to Chromatin.

Su(Hw) belongs to the class of proteins that organize chromosome architecture, determine promoter activity, and participate in formation of the boundaries/insulators between the regulatory domains. This protein contains a cluster of 12 zinc fingers of the C2H2 type, some of which are responsible for binding to the consensus site. The Su(Hw) protein forms complex with the Mod(mdg4)-67.

Impact of Interactions between Su(Hw)-Dependent Insulators on the Transvection Effect in Drosophila melanogaster.

Transvection is a phenomenon of interallelic communication in which enhancers can activate a specific promoter located on a homologous chromosome. Insulators play a significant role in ensuring functional interactions between enhancers and promoters. In the presented work, we created a model where two or three copies of the insulator are located next to enhancers and promoters localized on homologous chromosomes.

Development of a New Model System to Study Long-Distance Interactions Supported by Architectural Proteins.

Chromatin architecture is critical for the temporal and tissue-specific activation of genes that determine eukaryotic development. The functional interaction between enhancers and promoters is controlled by insulators and tethering elements that support specific long-distance interactions. However, the mechanisms of the formation and maintenance of long-range interactions between genome regulatory elements remain poorly understood, primarily due to the lack of convenient model systems.

The MADF-BESS Protein CP60 Is Recruited to Insulators via CP190 and Has Redundant Functions in .

Drosophila CP190 and CP60 are transcription factors that are associated with centrosomes during mitosis. CP190 is an essential transcription factor and preferentially binds to housekeeping gene promoters and insulators through interactions with architectural proteins, including Su(Hw) and dCTCF. CP60 belongs to a family of transcription factors that contain the N-terminal MADF domain and the C-terminal BESS domain, which is characterized by the ability to homodimerize.

The BEAF-32 Protein Directly Interacts with Z4/putzig and Chriz/Chromator Proteins in Drosophila melanogaster.

In Drosophila, the BEAF-32, Z4/putzig, and Chriz/Chromator proteins colocalize in the interbands of polytene chromosomes. It was assumed that these proteins can form a complex that affects the structure of chromatin. However, the mechanism of the formation of such a complex has not been studied.

HIPP1 stabilizes the interaction between CP190 and Su(Hw) in the Drosophila insulator complex.

Suppressor of Hairy-wing [Su(Hw)] is one of the best characterized architectural proteins in Drosophila and recruits the CP190 and Mod(mdg4)-67.2 proteins to chromatin, where they form a well-known insulator complex. Recently, HP1 and insulator partner protein 1 (HIPP1), a homolog of the human co-repressor Chromodomain Y-Like (CDYL), was identified as a new partner for Su(Hw).

The same domain of Su(Hw) is required for enhancer blocking and direct promoter repression.

Suppressor of Hairy-wing [Su(Hw)] is a DNA-binding architectural protein that participates in the organization of insulators and repression of promoters in Drosophila. This protein contains acidic regions at both ends and a central cluster of 12 zinc finger domains, some of which are involved in the specific recognition of the binding site. One of the well-described in vivo function of Su(Hw) is the repression of transcription of neuronal genes in oocytes.

Multiple interactions are involved in a highly specific association of the Mod(mdg4)-67.2 isoform with the Su(Hw) sites in .

The best-studied insulator complex consists of two BTB-containing proteins, the Mod(mdg4)-67.2 isoform and CP190, which are recruited to the chromatin through interactions with the DNA-binding Su(Hw) protein. It was shown previously that Mod(mdg4)-67.

Interactions between BTB domain of CP190 and two adjacent regions in Su(Hw) are required for the insulator complex formation.

The best-studied Drosophila insulator complex consists of two BTB-containing proteins, the Mod(mdg4)-67.2 isoform and CP190, which are recruited cooperatively to chromatin through interactions with the DNA-binding architectural protein Su(Hw). While Mod(mdg4)-67.

LTR sequence of the MDG4 retrotransposon contains the MAD protein binding site that affects the east-dependent repression.

Earlier, we showed in a model system of the yellow gene of D. melanogaster that an increase in the EAST protein concentration leads to repression in bristles, the mechanism of which remained obscure. In this study, an inverted repeat was localized by genetic methods in the long terminal repeat (LTR) sequence of the MDG4 retrotransposon.

Mapping the D.melanogaster En1A Enhancer Modules Responsible for Transcription Activation and Long-Distance Enhancer-Promoter Interactions.

The structure of the new enhancer En1A of the 1A region of the X chromosome of was investigated. Two distinct regulatory elements were found. The first element is responsible for transcription activation, and the second element provides specific interaction with the promoter of the gene.

Zinc finger domain of Su(Hw) protein is required for the formation of functional Su(Hw)-dependent insulator complex.

This study is devoted to clarifying the role of Mod(mdg4)-67.2 and Su(Hw) proteins in the interaction between Su(Hw)-dependent insulator complexes and identifying the specific domains of the Su(Hw) protein required for insulation or mutual neutralization of insulators. Using genetic techniques and experiments in yeast two-hybrid system, we have demonstrated that the zinc finger domain of the Su(Hw) protein is involved in forming a functional insulator complex and cannot be replaced with the DNA-binding domain of the GAL4 protein.