Primordial germ cells (PGCs) in mammals migrate from the hindgut at embryonic day 9 and enter the developing gonads by embryonic day 11.5. This migration is dependent upon tracts of extracellular matrix (ECM) proteins found outside the cells. Interaction of these proteins occurs with integral membrane receptors known as integrins, found in the plasma membrane of PGCs. Integrin receptors interact either with an RGD (i.e., arginine-glycine-aspartic acid) sequence found on the ECM protein or by a non-RGD recognition interaction.
To elucidate the type of interactions, an experimental setup is shown. PGCs are placed in a Petri dish, a glass coverslip is added to the bottom of the dish with or without an ECM protein, and the cell is cultured for 12 hours. The effects of an RGD competitive inhibitor peptide are shown.
Given the data, what is the best interpretation of the results? Select ALL that apply.
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a
PGCs can migrate along tracts of fibronectin in an RGD-dependent manner
b
PGCs can migrate along tracts of fibronectin in a non-RGD-dependent manner
c
PGCs can migrate along tracts of laminin in an RGD-dependent manner
d
PGCs can migrate along tracts of laminin in a non-RGD-dependent manner
e
PGCs cannot migrate on either fibronectin or laminin
a) PGCs can migrate along tracts of fibronectin in an RGD-dependent manner
c) PGCs can migrate along tracts of laminin in an RGD-dependent manner
The best interpretation of the results based on the given data is:
a) PGCs can migrate along tracts of fibronectin in an RGD-dependent manner.
c) PGCs can migrate along tracts of laminin in an RGD-dependent manner.
To determine the best interpretation of the results, we need to analyze the effects of the RGD competitive inhibitor peptide on PGC migration. The experimental setup involved placing PGCs in a Petri dish with or without an ECM protein (fibronectin or laminin) on a glass coverslip, and then culturing the cells for 12 hours.
Based on the given information, we can make the following interpretations:
a) PGCs can migrate along tracts of fibronectin in an RGD-dependent manner: If the presence of the RGD competitive inhibitor peptide significantly reduced or inhibited PGC migration on fibronectin, then this suggests that PGC migration on fibronectin is dependent on the RGD sequence. Therefore, option a is a possible interpretation.
b) PGCs can migrate along tracts of fibronectin in a non-RGD-dependent manner: If the presence of the RGD competitive inhibitor peptide did not affect PGC migration on fibronectin, then this suggests that PGC migration on fibronectin is not dependent on the RGD sequence. Therefore, option b is a possible interpretation.
c) PGCs can migrate along tracts of laminin in an RGD-dependent manner: If the presence of the RGD competitive inhibitor peptide significantly reduced or inhibited PGC migration on laminin, then this suggests that PGC migration on laminin is dependent on the RGD sequence. Therefore, option c is a possible interpretation.
d) PGCs can migrate along tracts of laminin in a non-RGD-dependent manner: If the presence of the RGD competitive inhibitor peptide did not affect PGC migration on laminin, then this suggests that PGC migration on laminin is not dependent on the RGD sequence. Therefore, option d is a possible interpretation.
e) PGCs cannot migrate on either fibronectin or laminin: If the presence of the RGD competitive inhibitor peptide significantly reduced or inhibited PGC migration on both fibronectin and laminin, then this suggests that PGC migration on both ECM proteins is dependent on the RGD sequence. Therefore, option e is a possible interpretation.
To determine the best interpretation, we would need to refer to the actual experimental results and analyze whether the presence of the RGD competitive inhibitor peptide had a significant effect on PGC migration on fibronectin and laminin.