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Class I major histocompatibility complex cDNA clones from sheep thymus: alternative splicing could make a long
D Grossberger1, W Hein, A Marcuz
1Basel Institute for Immunology, Switzerland.
Immunogenetics
|January 1, 1990
Summary
Researchers identified major histocompatibility complex (MHC) class I genes in young sheep thymus. They discovered a predominant gene sequence and an unusual variant, suggesting complex gene expression in sheep immunity.
Area of Science:
- Immunogenetics
- Molecular biology
Background:
- The major histocompatibility complex (MHC) plays a crucial role in immune responses.
- Understanding MHC gene expression in different species is vital for comparative immunology.
Purpose of the Study:
- To identify and characterize class I MHC genes expressed in the thymus of young sheep.
- To investigate the diversity and abundance of these gene transcripts.
Main Methods:
- Screening of a sheep thymus cDNA library using a human HLA-B7 cDNA probe under relaxed stringency conditions.
- Partial sequencing of isolated clones to determine gene classes and identify unique sequences.
- Comparative sequence analysis against known MHC sequences from other species.
Main Results:
- Thirteen cDNA clones representing sheep class I MHC genes were isolated.
- Sequences indicated the expression of at least three distinct loci, falling into five classes.
- One specific sequence was highly abundant, potentially representing the major expressed transcript in the thymus.
- An unusual clone exhibited a longer predicted cytoplasmic domain due to an intron retention event.
- Sheep class I MHC sequences showed highest similarity to bovine and lowest to mouse sequences.
Conclusions:
- Sheep thymus expresses diverse class I MHC genes, with a dominant transcript identified.
- An aberrant transcript suggests potential alternative splicing or post-transcriptional modification.
- Comparative analysis highlights evolutionary relationships of MHC genes across species.