The putative 15 S precursor of globin mRNA contains a poly (A) sequence

Area of Science:

• Molecular Biology
• RNA Biochemistry

Background:

• Globin messenger RNA (mRNA) synthesis in immature red blood cells is a key process for hemoglobin production.
• Understanding mRNA processing and precursor molecules is crucial for deciphering gene expression regulation.

Purpose of the Study:

• To identify and characterize globin-coding RNA species in chicken immature red blood cells.
• To investigate the presence and nature of polyadenosine (poly(A)) sequences in nuclear globin RNA precursors.

Main Methods:

• Isolation and fractionation of pulse-labeled nuclear RNA using denaturing sucrose gradients.
• Hybridization of RNA fractions with globin complementary DNA (cDNA) followed by RNase digestion.
• Poly(A) sequence detection via poly(U)-Sepharose chromatography and hydroxyapatite chromatography after specific enzymatic treatments.

Main Results:

• Two RNA species with globin coding sequences were identified: a 9S species (mature mRNA) and an approximately 15S species (precursor).
• The 15S RNA precursor was found to contain a poly(A) sequence.
• Poly(A) sequences of approximately 100 nucleotides were isolated from the 15S globin precursor RNA and were sensitive to RNase T2 digestion.

Conclusions:

• A precursor molecule for 9S globin mRNA exists in chicken immature red blood cell nuclei.
• This precursor molecule contains a poly(A) tail, suggesting its role in mRNA processing and transport.