2. Early L(1)sc expression: Are there L(1)sc equivalence groups? Stage 9 8 L(1)sc + cells Early Stage 10 All posterior cells L(1)sc + 9-10 L(1)sc + cells + MP3&4 Total of 11 -12 L(1)sc + cells Stage 10: 2 glia underneath MP3 lighter L(1)sc expression 7 lsc+ cells around MP4 Total of 11 l(1)sc+ cells

3. Lethal of Scute is Present in MPs and their Neuronal Progeny from Stages 9-11 L(1)Scpdm2/nubmerge Stage 10 Stage 11 Stage 12 Present in PMG (s10-12) Present in MNB Present in all MPs (MP4, MP3, MP1, MP5, MP6) and newly divided neurons (H-cell, H-cell sib; mVUM5,6 and iVUM5,6) Levels are asymmetric between H-cell and H-cell sib and between mVUM5 and iVUM5 l(1)sc may play a role in both neural precursor formation and establishing different daughter fates

4. Lethal of Scute is Present in MNB L(1)sc wor

5. Reduced Numbers of Neurons are Present in AS-C Mutants 6 elav + cells present from late 11-16 Suggests that reduced numbers of neurons not due to cell death, but less neurons are generated Stage 12Stage 14Stage 16 Wild -type Df(1)sc B57

6. AS-C Genes are Required for wor Expression wor: MNB Suggests MNB does not form and does not produce its 8 progeny wormerge Wild -type Df(1)sc B57

7. CG8965 and wrapper are unaffected in AS-C mutants wrapperCG8965 sc B57 :5 CG8965 + cells/seg 3.13 wrapper + CG8965 - cells/seg n= 8 seg High levels of wrapper did not always equal CG8965 + cells wt: 3 PMG/seg @ s14 n=2

8. AS-C genes are Required for tbh Expression 456 mVUM Tbh Cas Tkr iVUM Cas (mVUM4,5; iVUM4,5) Wild -type Df(1)sc B57 Tbh (mVUMs) merge Tkr (mVUM6; iVUM6) 60%50% Suggest that mVUM6 and iVUM6 are present 60%

9. AS-C Phenotype : Precursor Formation and Neuron-Specific Control MP1 H-cell sib mVUMiVUM AMG MP3 PMG MNB PMG MP4MP5MP6MP1AMG L(1)sc Notch Numb Neither Notch nor AS-C Both L(1)sc and Notch MNBp Wild-type

10. AS-C Phenotype : Precursor Formation and Neuron-Specific Control MP1 H-cell sib iVUM AMG MP3 PMG MNB PMG MP4MP5MP6MP1AMG L(1)sc Notch Numb Neither Notch nor AS-C Both L(1)sc and Notch AS-C mutant X X

11. 4 pdm2/nub + Neurons are Present in AS-C mutants pdm2/nub: MP1s, H-cell, H-cell sib pdm2/nub Stage 14 merge Wild -type Df(1)sc B57 MP1 H-cell sib mVUMiVUM MP3MP4MP5MP6MP1

12. AS-C Genes are Required for ple Expression pdm2/nub: MP1s, H-cell & H-cell sib present MP1 and H-cell sib gene expression unaffected AS-C genes required for H-cell specific gene expression Lim3 (MP1s) CG13565 (H-cell sib) ple (H-cell) Wild -type Df(1)sc B57 H-cell sib MP3 MP1

13. AS-C mutants acscl(1)scase D(f)sc 19 X-ray derivative of In(1)ac 3 pt mutation causes sc to lack C term Sc protein nonfunctional Rearrangement that separates all 5’ seq of ac Df(1)sc B57 acscl(1)scase XX XXXX X

14. Scute is Present in MPs, but not Neurons from Stages 10-11 Scpdm2/nubmerge Stage 10 Stage 11 Present in PMG (s10-11) Present in MP3, MP5, MP1, MP6, and MNB prior to division and is absent from newly divided neurons May play a role in neural precursor formation, but not in establishing different daughter fates

15. Achaete Expression Acpdm2/nubmerge Stage 10 Stage 11 Stage 12 Present in MP1 and transiently in MP5, MP6, and MNB Remains on in MP1 neurons to end of embryogenesis May play a role in precursor formation and in MP1 neuron development