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Molecular cloning and
functional characterisation of the human fertilin
b(FTN-b)
and SPAM1 promoters
Banu Az-Zubair M.K.
Department
of Molecular Biology and Bioinformatics, National
Biotechnology Development Agency, Area 11, Garki-Abuja,
Nigeria. E-mail:
azzubair@nabda.gov.ng.
Accepted
4 October, 2008 |
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Among the molecules that play an essential role in the early
steps of the process of fertilisation, and in the
interaction of the sperm with the egg, are the sperm
adhesion molecule 1 (SPAM1) and fertilin
b(FTN-b).
This interaction, mediated by various molecules on the
gametes, starts with sperm-egg adhesion and ultimately
results in the fusion of the membranes. The human fertilin
b(FTN-b)
and SPAM1 promoters were cloned and characterised to
determine their similarity with other testis germ
cells-specific promoters, and to assess their functionality
and tissue specificity. Various fragments of the promoters
were fused with GFP in an expression cassette for an in
situ transcription assay using four different cell
types. Transcription initiation sites (TSS) were mapped by
RACE at -127 nucleotide position relative to the initiation
codon (ATG) in SPAM1 and at -64 nucleotide position
in FTN-b.
Neither the SPAM1 nor FTN-b
promoter have consensus TATA or CCAAT boxes; however,
they have the initiator (Inr) motif at the transcription
initiation sites and the TSF (Testis Specific
Factor) motif pair, one in either orientation. In
addition FTN-b
has a DPE (downstream promoter element) at +30 position
relative to the transcription start site, while SPAM1
has CRE (Cyclic-AMP Response Element)
motifs at positions -28 and -70.
Key
words:
Spermatogenesis, germ cells, promoter, transcription. |
