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Expression of naturally occurring RNA molecules complementary to the murine L27' ribosomal protein mRNA
P Belhumeur1, M Lussier, D Skup
1Institut du Cancer de Montréal, Québec, Canada.
Abstract:
We report here the existence of two naturally occurring RNA molecules that are complementary to the murine L27' ribosomal protein (rp) mRNA. These transcripts are 1.8 and 1.0 kb in length, and are both found in poly(A)+ populations of cytoplasmic and polysomal RNA of a number of established cell lines and in all adult murine tissues examined with the exception of the testes, where only the 1.8-kb transcript was detected. The expression of the 1.8-kb transcript is also constant during mouse embryogenesis from days 11 through 18 of gestation, and during differentiation of P19 embryonal carcinoma cells, whereas that of the smaller transcript decreases at 14 days and was not detected in 16- and 18-day embryos or in differentiated P19 cells. At the structural level both countertranscripts share the same region of perfect or near perfect complementarity to the L27' rp mRNA, which spans more than 75% of the coding region of the latter. The 0.8-kb difference in length of the two countertranscripts lies mainly 3' of the divergence from complementarity to the rp sequence. Indirect evidence suggests that the countertranscripts do not originate from the active L27' rp gene copy. The possible biological significance of the co-existence of the countertranscripts with the housekeeping L27' rp mRNA within the same cell is discussed.
Insights
Two novel RNA molecules complementary to ribosomal protein L27
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Ribosomal proteins (rp) are essential components of ribosomes, responsible for protein synthesis.
- The murine L27' rp mRNA is a housekeeping gene, crucial for normal cellular function.
- The existence and function of naturally occurring RNA molecules complementary to specific mRNAs are not fully understood.
Purpose of the Study:
- To identify and characterize naturally occurring RNA molecules complementary to the murine L27' ribosomal protein (rp) mRNA.
- To investigate the expression patterns and structural features of these complementary RNA transcripts.
- To explore the potential biological significance of these countertranscripts in relation to the L27' rp mRNA.
Main Methods:
- RNA isolation from various cell lines and adult murine tissues.
- Northern blot analysis to detect and size RNA transcripts.
- Analysis of RNA populations (cytoplasmic, polysomal, poly(A)+).
- Comparative sequence analysis to determine complementarity.
Main Results:
- Two naturally occurring RNA molecules, 1.8 kb and 1.0 kb in length, complementary to L27' rp mRNA were identified.
- These countertranscripts were found in most adult murine tissues and cell lines, with the 1.8-kb transcript also present in testes.
- Expression of the 1.8-kb transcript was constant during embryogenesis and P19 cell differentiation, while the 1.0-kb transcript showed decreased expression and was absent in later developmental stages and differentiated cells.
- Both countertranscripts share a region of high complementarity to the L27' rp mRNA, spanning over 75% of its coding region.
- The length difference between the two countertranscripts is primarily located 3' to the complementary region.
- Indirect evidence suggests these countertranscripts do not originate from the active L27' rp gene.
Conclusions:
- The study reports the discovery of two novel RNA countertranscripts to the housekeeping L27' rp mRNA in mice.
- Differential expression patterns suggest distinct roles for the two countertranscripts during development and differentiation.
- The findings raise questions about the regulatory mechanisms and biological functions of these countertranscripts in cellular processes.