RESUMO
Myoneurin belongs to the BTB/POZ and zinc finger protein family whose members have been implicated in regulatory functions of gene expression. Myoneurin has been identified in various tissues, but muscle is a privileged site of myoneurin gene transcription. We examined the neuromuscular expression of myoneurin during development and after axotomy. Myoneurin expression is developmentally regulated in mouse muscle and appeared to be associated with neuromuscular junctions during the late embryonic period. Myoneurin is located in and around synaptic myonuclei in mouse and human adult muscle. The expression of myoneurin is dysregulated after nerve section. Thus, the restricted myoneurin expression in synaptic myonuclei appeared to be controlled by muscle electrical activity. Myoneurin is identified within the peripheral condensed chromatin and the euchromatin/heterochromatin regions, and thus fulfills structural and expression criteria to represent a synaptic gene regulator.
Assuntos
Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Junção Neuromuscular/metabolismo , Fatores de Transcrição/metabolismo , Dedos de Zinco , Animais , Axotomia , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Cromatina/genética , Cromatina/metabolismo , Cromatina/ultraestrutura , Proteínas de Ligação a DNA , Modelos Animais de Doenças , Regulação da Expressão Gênica no Desenvolvimento/genética , Humanos , Fatores de Transcrição Kruppel-Like , Camundongos , Microscopia Eletrônica , Denervação Muscular , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/ultraestrutura , Músculo Esquelético/ultraestrutura , Junção Neuromuscular/embriologia , Junção Neuromuscular/ultraestrutura , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/ultraestrutura , Membranas Sinápticas/metabolismo , Membranas Sinápticas/ultraestrutura , Transmissão Sináptica/genética , Regulação para Cima/genética , Dedos de Zinco/genéticaRESUMO
A new family of human endogenous retroviruses has recently been discovered. The best known example of a full length member of this family, HERV-W/7q, is located on chromosome 7. HERV-W/7q is characterized by a long open reading frame within its env gene which is expressed in various tissues, and mainly in placenta, as a protein that we called enverin. A search for new retroviral sequences related to the HERV-W/7q family allowed the characterization of such elements in chromosome 6. A novel full length HERV with an env gene of the HERV-W/7q type, potentially encoding a truncated form of enverin has been identified on chromosome 10. The distribution of HERV-W/7q related sequences close to or within genes offers the possibility that the expression of these genes may be regulated by their companion retroviral sequences.
