Final answer:
The two subunits in chromatin remodeling are ATP-dependent chromatin remodelers and histone chaperones. These subunits facilitate changes in chromatin structure, either by repositioning nucleosomes or by assembling and disassembling them, which affects the transcriptional activity of genes.
Step-by-step explanation:
The two subunits involved in chromatin remodeling are ATP-dependent chromatin remodelers and histone chaperones. ATP-dependent chromatin remodelers utilize energy from ATP hydrolysis to reposition nucleosomes, which affects the accessibility of DNA to the transcription machinery. Histone chaperones are involved in the assembly and disassembly of nucleosomes, which also plays a critical role in the regulation of gene expression.
Chromatin remodeling is crucial for regulating gene transcription in non-dividing cells or during interphase. It involves alterations in chromatin conformation through chemical modifications such as histone acetylation, methylation, and phosphorylation by various enzymes, such as HAT enzymes (Histone Acetyltransferases), de-acetylases, methyltransferases, and kinases. These modifications can either increase accessibility to DNA for transcription or promote DNA condensation and gene silencing.
The process of chromatin remodeling is dynamic, allowing genes to be turned on or off as needed. The cellular machinery can add or remove chemical groups, including phosphate, methyl, and acetyl groups, to alter the charge and binding affinity of histones to DNA. The open or closed state of chromosomal regions is regulated by these epigenetic changes, dictating whether transcription factors can access the DNA and initiate gene expression.