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nbme24/Block 3/Question#17

HOX genes play a role in embryogenesis through ...

Regulation of transcription

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submitted by m-ice(184),

All HOX genes are transcription factors that help regulate body layout and different expression of genes for each body segment.

sunshinesweetheart  I got this one right but wasn't exactly sure how to rule out 'translation'. I guess just because we're talking about a gene i.e. trasncription and not miRNA i.e. post-translational modifiers? +  

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submitted by ibrahim(2),

Hox genes come from a family of homeobox genes that encode transcription factors. These transcription factors bind to the DNA and allow for activation or repression of specific genes. Hox genes are primarily responsible for patterning of the anterior-posterior axis of the vertebrate embryo and limb bud. A characteristic unique to Hox genes is that they are found in clusters, instead of scattered across the genome as most genes are. This clustering of the genes allows for the sequential expression during development to correctly form body parts. However, if there is a mutation in these genes it can cause syndactyly, polydactyly, an extra cervical rib, and an increased risk of cancer.

Vitamin A is a teratogen that can lead to spontaneous abortion if taken in excess. Its use has also been shown to lead to developmental defects of the central nervous system and can lead to the disruption of Hox genes. Vitamin A can be found in a variety of foods including yellow vegetables, dark leafy greens, liver, and eggs. RX Q BANQ