I am looking a axonal transport in drosophila larval sensory neurons.

When i compared the endogenous expression vs. the overexpression constructs of the following proteins i saw soluble vs vesicular movement respectively.

1. Bloom ID 62542 y[1] w[1118]; TI{TI}Rab4[EYFP] expression: soluble

2. Bloom ID 23269 y[1] w[*]; P{w[+mC]=UASp-YFP.Rab4}09 expression: punctate (driven by chatGal4)

1. BLOOM ID 60930 y[1] w[*]; Mi{y[+mDint2]=MIC}nSyb[MI11038]/TM3, Sb[1] Ser[1] expression: soluble

2. BLOOM ID 6921 w[*]; P{w[+mC]=UAS-nSyb.eGFP}2

expression: Punctate

I imaged with a confocal microscope with 0.104um pixel size, HSD detector.

The GFP/YFP tag in the ndogenous contructs is not cleaved as i can see enrichment at the synapse.

What could be the reason for this discrepancy then?