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Abstract
DNA polymerase β is involved in the repair machinery for DNA damage
through single base excision repair and gap filling. It is a specialized type of
polymerase, encoded by a gene that if is over-expressed, under-expressed
or alternatively spliced, a tumour genesis chain may be provoked as well as
tolerance to DNA damaging agents, such as geno-toxic chemotherapy, UV
light and oxidative stress. Identification of splice variants of the polymerase
β mRNA has been documented in many malignant diseases such as bladder,
colorectal and breast cancers. In blood cells, splice variants of DNA
polymerase β in haematological cell lines using PCR based techniques. This
study demonstrate the presence of an intron 9 inclusion, excon 2 deletion
and exon 11 deletion splice variants in normal B-lymphocytes commercial
cell line AGLCL. Exon 2 deletion splice variants was shown to be the most
frequently expressed variant followed by exon 11 deletion, both variants of
exon 2 deletion and exon 11 deletion were found to be expressed almost
equally in the cell samples of the AGLCL cell line and were not influenced by
the type of geno-toxic treatment such as chemotherapy and oxidative
stress. On the other hand, intron 9 inclusion splice expression appeared to
be influenced by exposure to oxidative stress in combination with the genotoxic chemotherapeutic agent melphalan. Moreover, novel splice various
molecular weight were identified in all of the examined cell samples. It is
recommended to investigate these splice variants further by cloning and
sequencing and to examine their translation proteins.