Comparison of the mouse L32 ribosomal protein promoter elements in mouse myoblasts, fibers, and L cells

Abstract

The sequences required for the maximal expression of the mouse L32 ribosomal protein gene and the binding of nuclear factors to L32 promoter elements were analyzed in mouse myoblasts, fibers, and L cells. Various L32 r-protein promoter sequences were linked to the chloramphenicol acetyltransferase gene (CAT), and the expression of the chimeric genes was measured transiently or after their incorporation into the genome. The sequence requirements for maximal expression of the L32 gene are very similar among the various cells and include the previously identified L32 core promoter from approximately -150 to +75. Only the promoter regions between -45 and +11 displays significant cell type specific differences. Relative to the maximal activity in each cell type, the expression of the L32-CAT gene containing the -45 to +11 region is greater in L cells than in myoblasts or fibers. This difference is correlated with the increased activity of an L cell nuclear factor(s) that binds to this fragment. In addition, our results show that deletion of sequences between -981 and -141 causes a 50-70% reduction of the expression of the L32-CAT gene in myoblasts, fibers and L cells. The transcription of all the L32-CAT genes examined decrease after myoblasts differentiate into fibers in a manner similar to the endogenous L32 gene, but we were unable to distinguish between sequences involved in controlling the expression of the L32 gene during myoblast differentiation and those sequences required for maximal promoter activity. However, gel mobility shift assays showed differences in the binding of myoblast and fiber factors to the four promoter fragments examined. The possible role of these factor binding differences in controlling L32 transcription is discussed.

Ribosomal protein S19 expression during erythroid differentiation

“…These results were in accordance with the general features of other mammalian ribosomal protein gene promoters, as previously described for the mouse RPL30, 10,11,[26][27][28]10,[27][28][29][30][31][32][33][34][35]34,[36][37][38] genes. These features included (1) location of regulatory transcription elements in a short region of 200 nt immediately upstream of the transcriptional start site; (2) existence of regulatory elements located downstream of the transcription cap; and (3) regulatory elements close to the cap site which play a major role in the promoter function.…”

Bone marrow cells from patients with Shwachman‐Diamond syndrome abnormally express genes involved in ribosome biogenesis and RNA processing

“…This is probably achieved by ensuring an equivalent loading of RNA polymerases on the RP gene promoters (Hariharan et al , 1989) and a comparable strength of these promoters in driving RP expression (Hariharan et al , 1989). Several cis ‐acting regulatory elements and transcription factor binding sites of mammalian RP genes have been studied (Hariharan & Perry, 1989; Hariharan et al , 1989; Meyuhas & Klein, 1990; Colombo & Fried, 1992; Harris et al , 1992; Yoganathan et al , 1992; Chung & Perry, 1993; Genuario et al , 1993; Overman et al , 1993; Davies & Fried, 1995; Safrany & Perry, 1995; Genuario & Perry, 1996; Curcic et al , 1997; Antoine & Kiefer, 1998; Kirn‐Safran et al , 2000). No regulatory element common to all RP genes has been identified, although certain elements were present in several of the genes that were studied.…”

GA-binding protein is involved in altered expression of ribosomal protein L32 gene

“…This delay in transcription, implies, however, that other factor(s), beside those already identified, may limit rpL32 gene transcription. A report by Harris et al [1992] indicated that binding of the factors to the rpL32 gene promoter were quite different in MM14 myoblasts, as compared to fiber extracts. In addition, they reported that sequences upstream of 2141 are also required for expression of the rpL32 gene, since deletion of that region reduced mRNA levels by 50-70% in mouse MM14 myoblasts [Harris et al, 1992].…”

“…A report by Harris et al [1992] indicated that binding of the factors to the rpL32 gene promoter were quite different in MM14 myoblasts, as compared to fiber extracts. In addition, they reported that sequences upstream of 2141 are also required for expression of the rpL32 gene, since deletion of that region reduced mRNA levels by 50-70% in mouse MM14 myoblasts [Harris et al, 1992]. A stimulatory effect of these upstream sequences has not been detected previously in COS or mouse plasmacytoma cells [Dudov and Perry, 1986;Atchison et al, 1989;Moura-Neto et al, 1989].…”

“…Although a downshift in the rate of ribosome production occurs and transcription of the rRNA gene is suppressed in both systems following myoblasts differentiation, balanced production of the ribosomal proteins is achieved by different mechanisms [Krauter et al, 1979;Jacobs et al, 1985;Agrawal and Bowman, 1987]. Decreased synthesis of rpL32 in mouse MM14 myotubes is controlled by a decrease in the steady state level and translational efficiency of rpL32 mRNA [Agrawal and Bowman, 1987;Harris et al, 1992]. In contrast, differentiation of rat L6 myoblasts to multinucleated myotubes display no change in the rate of transcription of the rpL32 gene [Jacobs et al, 1985].…”