Sequences and evolution of mammalian RH gene transcripts and proteins

Area of Science:

• Biochemistry
• Evolutionary Biology
• Genomics

Background:

• The Rh blood group system is crucial for transfusion medicine.
• Understanding the evolutionary history and molecular variations of Rh proteins is essential.

Purpose of the Study:

• To investigate the presence and characteristics of Rh30-like polypeptides in various mammalian erythrocyte membranes.
• To analyze the amino acid variability and evolutionary relationships of Rh-like proteins across mammalian species.

Main Methods:

• Immunoblotting was used to detect Rh30-like polypeptides in erythrocyte membranes.
• Rh-like transcripts from nonhuman primates and mice were amplified and sequenced.
• Phylogenetic analysis was employed to estimate the coalescence time of mammalian Rh cDNA sequences.

Main Results:

• Rh30-like polypeptides (33 kDa) were detected in nonhuman primate and nonprimate mammal erythrocyte membranes.
• Amino acid sequence analysis showed significant variability in extramembrane loops, especially the sixth external loop, compared to transmembrane domains.
• Phylogenetic analysis estimated the coalescence of mammalian Rh cDNA sequences at approximately 100 million years ago.

Conclusions:

• Mammalian Rh-like proteins exhibit distinct variability patterns, with extramembrane regions being more diverse.
• The evolutionary divergence of mammalian Rh genes dates back at least 100 million years.
• This study provides insights into the molecular evolution and structural diversity of Rh-like polypeptides across mammals.