The TE Promoter Element of the Histone H1t Gene Is Essential for Transcription in Transgenic Mouse Primary Spermatocytes1

Abstract

Transcriptional activation of the testis-specific histone H1t gene occurs in pachytene primary spermatocytes during spermatogenesis. Specific binding of testis nuclear proteins to a rat histone H1t promoter sequence, designated the H1t/TE element, correlates with the onset of transcription. This element, located between the H1t/AC box and the H1t/CCAAT box, contains inverted repeats of a shorter element. When the native rat H1t gene along with flanking sequences, including 2453 base pairs (bp) upstream and 3784 bp downstream from the coding region, was microinjected into mouse embryos, the offspring of the resulting transgenic mice transcribed the transgene in a tissue-specific manner and only in primary spermatocytes. In the present study the TE promoter element was deleted and replaced with a heterologous stuffer DNA fragment. When the mutant rat DNA fragment was used to create transgenic mice, offspring of the mice bearing the promoter mutation did not transcribe the rat H1t gene in any tissue. On the other hand, transcription of the rat H4t transgene, which is located approximately 1.5 kilobases downstream from the H1t gene, occurred in these animals. Therefore, these studies support the hypothesis that the TE element is essential for enhanced testis-specific transcription of the H1t gene in primary spermatocytes.

Germline-specific H1 variants: the “sexy” linker histones

“…A testis-specific regulatory element (TE) provides testis-specific expression of H1t (Grimes et al 1990, 1992a. TE is essential for H1t transcription in primary spermatocytes since its replacement by a heterologous DNA abolishes expression in transgenic mice (vanWert et al 1998). TE contains two inverted repeat sequences, TE1/X-box1 and TE2/X-box2, and a GC-box located between these two elements (Wolfe et al 1995).…”

The first bromodomain of Brdt, a testis-specific member of the BET sub-family of double-bromodomain-containing proteins, is essential for male germ cell differentiation

“…To test this hypothesis, we performed chromatin immunoprecipitation (ChIP) experiments using affinitypurified ␣-CT antibody and primers against the H1t proximal and distal promoter region. The primers were selected based on previous studies showing that the proximal and distal regions are involved in the activation and repression of H1t expression, respectively (vanWert et al, 1998;Wolfe et al, 1999). The results revealed that immunoprecipitated full-length Brdt protein (from control testes) was found in association with the distal region of the histone H1t promoter (-806 to -1027 from the transcription initiation site), but not to the more proximal region of the promoter (Fig.…”

Specific Binding of Nuclear Proteins to a Bifunctional Promoter Element Upstream of the H1/AC Box of the Testis-Specific Histone H1t Gene1

“…Within the H1t promoter, additional elements are important for testis-specific expression of the histone H1t gene [4,6,10,11,15,20]. These include those that are involved in transcriptional activation of the gene in primary spermatocytes and those that are involved in transcriptional repression in other cell types.…”

“…Previous studies revealed the importance of the proximal promoter and of testis element (TE) located between the H1/AC box and the H1/CCAAT box [13,14]. When TE is replaced by a heterologous DNA sequence, expression of the mutant rat H1t gene is disrupted in transgenic mice [11,15].…”