Choriogonadotropin subunit beta variant 1 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
that in humans is encoded by the ''CGB1''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
The beta subunit of
chorionic gonadotropin
Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantation ...
(CGB) is encoded by six highly
homologous and structurally similar genes that are arranged in tandem and inverted pairs on
chromosome 19q13.3, and contiguous with the
luteinizing hormone beta (LHB) subunit gene. The CGB genes are primarily distinguished by differences in the 5' untranslated region. This gene was originally thought to be one of the two
pseudogenes
Pseudogenes are nonfunctional segments of DNA that resemble functional genes. Most arise as superfluous copies of functional genes, either directly by DNA duplication or indirectly by reverse transcription of an mRNA transcript. Pseudogenes are ...
(CGB1 and CGB2) of CGB subunit, however, detection of CGB1 and CGB2 transcripts in vivo, and their presence on the
polysomes, suggested that these transcripts are translated. To date, a protein product corresponding to CGB1 has not been isolated. The deduced sequence of the hypothetical protein of 132 aa does not share any similarity with that of functional CGB subunits (). However, a 155 aa protein, translated from a different frame, is about the same size, and shares 98% identity with other CGB subunits.
References
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External links
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{{gene-19-stub