Testis-specific transcription initiation sites of rat farnesyl pyrophosphate synthetase mRNA.

Abstract

A variety of rat tissues were screened at low stringency with a rat farnesyl pyrophosphate (FPP) synthetase cDNA. In testis, an FPP synthetase-related RNA was detected that was larger than the liver FPP synthetase mRNA and was present at very high levels comparable with liver FPP synthetase RNA levels obtained from rats fed diets supplemented with cholestyramine and mevinolin. Sequence analysis of testis cDNA clones, together with primer extension and Sl nuclease experiments, indicated that testis FPP synthetase transcripts contain an extended 5' untranslated region. The 5' extension contained one or two out-of-frame upstream ATGs, depending on the site of transcription initiation. Protein in vitro translation studies indicated that the extended 5' untranslated region may play a role in regulating the translation of the FPP synthetase polypeptide in rat testis. Southern blot analysis with a probe containing both testis and liver 5' untranslated sequences provided evidence that both liver and testis transcripts derive from the same gene. The data suggest that an upstream testis-specific promoter results in the abundant production of FPP synthetase transcripts that are translated at low efficiency; another promoter functions in liver and other somatic tissues and directs the regulated synthesis of shorter discrete transcripts.

Novel Repeat Elements Direct Rat Proenkephalin Transcription during Spermatogenesis

“…In other cases, novel untranslated sequences are present that may have specific regulatory roles, as in the translational control of testis-specific superoxide dismutase-1 mRNA involving its 5Ј-untranslated region (31). Transcription from an alternate spermatogenic cell-specific promoter is often involved in generation of these unique transcripts (32)(33)(34), as for rat and mouse proenkephalin. Alternate promoters expressed in somatic cells frequently function selectively during cell development and differentiation (35).…”

Expression of a Novel, Sterol-Insensitive Form of Sterol Regulatory Element Binding Protein 2 (SREBP2) in Male Germ Cells Suggests Important Cell- and Stage-Specific Functions for SREBP Targets during Spermatogenesis

“…Adult spermatogenic cells contain considerable concentrations of free and total cholesterol (greater than those in Sertoli cells) (2), and the expression of several genes involved in the cholesterol biosynthetic pathway increases during male germ cell maturation. These include the mRNAs for CYP51 and farnesyl pyrophosphate synthetase, both of which are up-regulated in round spermatids (38,47), and squalene synthase mRNA, which is expressed at similar levels in pachytene spermatocytes and round spermatids (38,46). Other SREBP targets increase in the testis with maturation, which at least suggests their expression in later stages of spermatogenesis.…”

Rat Phospholipid-hydroperoxide Glutathione Peroxidase

“…Although these 5Ј-sequences were derived from the longest cDNA clones that were obtained, it is not known whether they represent the major form of the mRNA in these tissues. In an analogous system, the rat farnesyl-pyrophosphate synthetase gene promoter contains testis-specific transcription start sites that are located 25-100 nucleotides upstream of the somatic start sites (30). The somatic start sites are clustered into two groups that are preceded by TATA boxes.…”