Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Genetics, Development and Cell Biology

First Advisor

Carol M. Warner


The major histocompatibility complex (MHC) is a group of genes coding for molecules that provide the context for the recognition of foreign antigens by T lymphocytes. This chromosomal region contains a large number of genes whose products play particularly important roles in a number of cellular processes of the immune system;The genes of the MHC are prime candidates for genetic engineering of domestic species because of their importance in many biological phenomena, including disease resistance and reproduction. To analyze the molecular structure of the chicken MHC, cDNA clones coding for chicken MHC class II (B-L) [beta] chain molecules were isolated from spleen and liver. Tissue-specific transcription of B-L [beta] genes was studied by Northern blot analysis. A high level of expression was detected for poly(A)[superscript]+ RNA isolated from spleen whereas a faint signal was detected for liver poly(A)[superscript]+ RNA;Twenty-nine cDNA clones were isolated from the spleen (S clones) and 8 cDNA clones were isolated from the liver (L clones). The restriction map of each of these clones showed that there were at least three families of cDNAs from the chicken of the B[superscript]6 haplotype. The largest cDNA clone from each unique family of genes (3 for spleen and 1 for liver) was sequenced. Complete amino acid sequences of B-L [beta] chain molecules, predicted from the nucleotide sequences of the [beta] chain cDNA clones, S19, S3, S10, S7, and L1, were determined. Nucleotide and amino acid sequence comparison to CCII-4 and CCII-7, which are genomic genes obtained from sperm of a chicken of the same haplotype, suggested a possible gene conversion mechanism in the process of development of mature adult cells;The nucleotide and the amino acid sequences of the chicken MHC [beta] chain genes permitted phylogenetic comparisons with the mammalian sequences and gave some insight into the evolution of the MHC. Although both the nature and the location of the conserved residues were similar in chicken and mammalian sequences, some species-specific differences were found, suggesting that the structures of the B-L molecules may not be identical to their mammalian counterparts.



Digital Repository @ Iowa State University,

Copyright Owner

Aree Moon Sung



Proquest ID


File Format


File Size

175 pages

Included in

Biochemistry Commons