Related Experiment Videos
Rat pulmonary surfactant protein A is expressed as two differently sized mRNA species which arise from differential
J H Fisher1, P A Emrie, J Shannon
1Department of Medicine, University of Colorado Health Sciences Center, Denver 80262.
Abstract:
In rat, the surfactant-associated glycoprotein A, SP-A, is encoded by two mRNA species of 0.9 and 1.6 kb. Each transcript is polyadenylated and is found in approximately the same ratio in total cellular RNA isolated from either alveolar type II cells or from whole lung. The two mRNA species have identical coding regions and differ only in the length of the 3' untranslated sequences. Restriction analysis and partial sequence analysis of rat genomic clones indicate that each mRNA species arises from one gene, with the difference in size most easily accounted for by differential polyadenylation. During fetal development, the accumulation of mRNA encoding SP-A is detectable by day 18 but increases many-fold on day 19. However, there are no apparent alterations in the prevalence of either mRNA species during fetal development or in the early postnatal period.
Insights
Surfactant-associated glycoprotein A (SP-A) in rats is produced from two mRNA types differing in 3' untranslated regions. Their gene expression and ratios remain consistent during development and early postnatal periods.
Area of Science:
- Molecular Biology
- Pulmonary Medicine
- Genetics
Background:
- Surfactant-associated glycoprotein A (SP-A) is crucial for lung function.
- SP-A is encoded by mRNA transcripts in rat lungs.
- Understanding SP-A gene expression is vital for respiratory health research.
Purpose of the Study:
- To investigate the molecular characteristics of SP-A mRNA in rats.
- To analyze the origin and regulation of different SP-A mRNA species.
- To examine SP-A mRNA expression patterns during rat lung development.
Main Methods:
- RNA isolation from rat alveolar type II cells and whole lung.
- Analysis of mRNA species size (0.9 kb and 1.6 kb).
- Restriction and partial sequence analysis of rat genomic clones.
- Fetal and early postnatal developmental studies.
Main Results:
- Two SP-A mRNA species (0.9 and 1.6 kb) were identified, differing in 3' untranslated regions but sharing identical coding sequences.
- Each mRNA species originates from a single gene, likely due to differential polyadenylation.
- SP-A mRNA accumulation begins by day 18 of fetal development, increasing significantly by day 19.
- The relative prevalence of the two mRNA species remained constant throughout development and the early postnatal period.
Conclusions:
- Rat SP-A is encoded by two mRNA variants arising from differential polyadenylation of a single gene.
- SP-A mRNA expression is developmentally regulated, with significant accumulation during late fetal development.
- The ratio of the two SP-A mRNA species is maintained during lung development and maturation.