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Role of an Insulator in Testis‐specific Gene Transcription
Author(s) -
REDDI PRABHAKARA P.,
UREKAR CRAIG J.,
ABHYANKAR MAYURESH M.,
RANPURA SANDEEP A.
Publication year - 2007
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1411.012
Subject(s) - promoter , enhancer , biology , gene , transcription (linguistics) , chromatin , somatic cell , gene expression , regulation of gene expression , insulator (electricity) , microbiology and biotechnology , transgene , genetics , linguistics , philosophy , electrical engineering , engineering
: Testis‐specific promoters are unique in that relatively short proximal promoters of several genes have been shown to be capable of directing tissue‐ and cell‐type‐specific expression in transgenic mice. How such small promoter fragments perform the dual functions of maintaining a silenced state in somatic tissues and activating gene expression in the correct germ‐cell type in testis remains poorly understood. Studies from our laboratory using the round spermatid‐specific SP‐10 gene as an experimental model have provided some insights into the mechanisms involved. It was found that the proximal promoter of the SP‐10 gene acts as a chromatin insulator or boundary element in somatic tissues and prevents transcription of the SP‐10 gene. In round spermatids, the insulator function is relieved, thus facilitating the SP‐10 gene transcription. Insulators act as enhancer blockers and/or barriers to heterochromatin to protect the programmed expression of a gene. Typically, insulators are separable from promoters. In the case of the SP‐10 gene, however, the insulator overlaps the promoter and operates in a facultative manner. We hypothesize that the proximal promoters of some testis‐specific genes have adapted the insulator function to maintain transcriptional silence in the somatic tissues.