0:00
Hello, this is Jim Kaufman
from the University
of Edinburgh and
the University of Cambridge
with the second of
two lectures on the
MHC and MHC molecules.
0:12
In our last talk,
we defined MHC molecules
and discussed their
central role.
We considered the classical class
I and class II MHC molecules
and the non-classical MHC
molecules in some detail
and we finished with the
organisation of MHC genes
in the MHC of humans and mice.
In the second talk,
we're going to consider
more closely genetics,
nomenclature, polymorphism
and function.
Then ask the
question what drives
the high polymorphism of
classical MHC molecules?
0:45
Last time we finished
with this picture
of the human and mouse MHCs,
which are extremely complex
with hundreds of genes,
including those encoding the
classical and non-classical
MHC molecules.
Let's discuss the nomenclature,
particularly of the
classical MHC molecules.
1:05
How are these genes named?
Starting with the
classical class I genes.
For humans, these genes are
called HLA -A, B, and C.
For mouse H-2K, D, and
in some haplotypes, L.
As we mentioned last time,
these genes are due to
different expansions.
HLA-A, B, and C genes
are more closely related
to each other than they are
to any of the mouse genes.
For the classical
class II genes,
there's HLA-DRA and DRB
for the DR α and β gene,
and likewise DQA and
DQB and DPA and DPB.
In mouse, there's H2Eα and Eβ.
But unlike class I genes,
these are direct orthologs
of the human DRA and DRB.
Similarly, H-2Aα and H-2Aβ
are orthologs of DQA and DQB.
But there are no mouse
orthologs of DPA and DPB.
However, there is
a second DRB locus
in most human haplotypes.
The major one is
always called DRB1;
the others have names
like DRB3, DRB5, etc.
