c-Myc is a predominantly nuclear transcription factor that is a substrate for rapid turnover by the proteasome system. Cancer-related mutations in c-Myc lead to defects in its degradation and thereby contribute to the increase in its cellular level that is associated with the disease. Little is known about the mechanisms that target c-Myc to the proteasomes. By using a GFP fusion protein and li...

Significance We discovered that the histone/protein deacetylase SIRT7, which is only member of mammalian sirtuin family residing primarily in nucleolus, stabilizes p53 response to UV-induced DNA damage by enabling binding deacetylated NPM MDM2/HDM2. The study unveils a crucial mechanism nucleolus controls cellular stress responses. Furthermore, it characterizes SIRT7 as potent regulator and off...

The effects of hyperthermia on chromatin condensation and nucleoli disintegration, as visualized by induction of premature chromosome condensation in interphase mammalian cells, was studied in exponentially growing and plateau phase Chinese hamster ovary cells. Exposure to heat reduced the ability of interphase chromatin to condense and the ability of the nucleolar organizing region to disinteg...

human mitochondrial dna (mtdna) is 16,569 base pairs (bp) in length, coding for 37 genes. during the course of evolution, nearly all the genes expressing ribosomal proteins and ribosomal rnas (rrna) genes have been transferred from the mitochondria to the nucleus. however, mitochondrial dna contains two ribosomal rnas genes (12s and 16s), which have not yet transferred to the nucleus. these two...

Polyribocytidylate-(3)H-polyriboinosinate (rC-(3)H:rI) enters cultured rabbit kidney cells from the surrounding medium within (1/2) hr after exposure. Grains are found in the cytoplasm, nucleus, and nucleolus. At 2 hr, grains are localized predominantly over the nucleolar regions. Subsequently, the grains in the nucleus become dispersed. A specific receptor site for the initiation of interferon...

Actin works in concert with myosin I to regulate the transcription of ribosomal genes in the nucleolus. Recently, nucleolar actin has been shown to be active in its polymeric form raising the question how actin dynamics is regulated in the nucleolus. Here, we show that the actin capping protein CapG localizes in the nucleolus of cultured cells. CapG transport to the nucleolus is an active and A...

The HIV-1 Rev protein localizes predominantly to the nucleolus of HIV-1-infected or Rev-expressing cells. The subcellular location of Rev during mitotic nucleolar disintegration was examined at various stages of mitosis in synchronized Rev-expressing CMT3 cells. During early prophase Rev was predominantly located in disintegrating nucleoli and began to accumulate at the peripheral regions of ch...

Methyl-CpG binding domain (MBD) proteins in Arabidopsis thaliana bind in vitro methylated CpG sites. Here, we aimed to characterize the binding properties of AtMBDs to chromatin in Arabidopsis nuclei. By expressing in wild-type cells AtMBDs fused to green fluorescent protein (GFP), we showed that AtMBD7 was evenly distributed at all chromocenters, whereas AtMBD5 and 6 showed preference for two ...